TREATISE 


ON 


.MARINE  AID  NAVAL  ARCHITECTURE 


OR 


THEORY    AND    PRACTICE 


BLENDED  IN 


SHIP   BUILDING. 


BY 

JOHN    W.    GRIFFITHS, 

MARINE    AND    NAVAL    ARCHITECT. 


ILLUSTRATED  WITH  MORE  THAN  FIFTY  ENGRAVINGS. 


$l)irb  (ftrttion. 


NEW- YORK: 

D.    APPLETON    &    COMPANY,    200    BROADWAY. 

LONDON:   JOHN  WEALE,  59  HIGH  HOLBORN. 

1 85a. 


M 


Entered  according  to  Act  of  Congress,  in  the  year  1849, 
BY  JOHN   W.   GRIFFITHS, 

In  the  Clerk's  Office  of  the  District  Court  of  the  United  States,  for  the 
Southern  District  of  New- York. 


N/rv) 


EXPLANATION  OF  CHARACTERS; 

ALSO,  DECIMAL  AND  FRACTIONAL  PARTS  OF  A  FOOT,  USED  IN  THE  WORK. 


=Equal  to,  as  144  square  inohes=I  square  foot. 

+  Plus,  or  more,  signifies  addition,  as  3+3+6+9=21. 

—Minus,  or  less,  signifies  subtraction,  as  10 — 5=5. 

X  Multiplication,  or  multiplied  by,  or  into,  as  7x9=63. 

-^Signifies  division,  as  63-^9=7. 

:  ::  :  Signifies  proportion  that  is,  as  3  :  6 "18  :  36. 

.  Decimal  point  signifies,  when  prefixed  to  a  number,  that  the  number  has  a  unite  for  its  denominator, 
as  .1  is  TV.01  is  j^j,  or  .792TWo- 

The  decimal  parts  of  a  foot  are  expressed  in  the  table  on  the  left ;  and  the  common  fractional  parts  of 
the  foot,  as  found  on  the  12  inch  rule,  will  be  found  in  the  tables  on  the  right :  the  latter  is  used  in  taking 
off  tables  from  the  model  ;  the  former  is  used  in  tables  of  displacements.  The  decimal  and  fractional 
parts  will  apply  equally  to  all  the  inches  of  the  foot,  as  well  as  the  first. 


1 

af  an  i 

nch 

,  0.01 

1 

4 

u 

ic 

0.02 

3 

8 

It 

it 

0.03 

I 

<c 

ii 

0.04 

5 
8 

CI 

ii 

0.05 

3 
4 

If 

ii 

0.06 

7 
8 

II 

ii 

0.07 

1 

inch 

0.08 

2 

inches 

0.17 

3 

ii 

0.25 

4 

ii 

0.33 

5 

ii 

0.42 

6 

ii 

0.5 

7 

it 

0.58 

8 

it 

0.66 

9 

ii 

0.75 

10 

it 

0.83 

11 

ii 

0.92 

12 

ii 

1. 

Ft.    In. 
0      0 

Eighths. 

1,  or  |-  of  an 

inch 

0     0 

2, 

11  ]       II 

4 

tt 

0     0 

3, 

II    3           II 

8 

it 

0     0 

4, 

11  1       II 

2 

it 

0     0 

5, 

It    5          It 

8 

it 

0     0 

6, 

II    3.        It 
4 

it 

0     0 

7, 

II   i          II 

8 

ii 

0     1 

0 

1  inch. 

0     2 

0 

0     3 

0 

0     4 

0 

0     5 

0 

0     6 

0 

0     7 

0 

0     8 

0 

0     9 

0 

0  10 

0 

0  11 

0 

1     0 

0 

«' 


CONTENTS. 


CHAPTER  I. 

Early  History  of  Ship  Building — The  cause  of  its 
Decline — Its  Revival  during  the  Middle  Ages — 
Reasons  why  so  little  is  known  of  the  Art  from 
History — Equilibrium  of  Fluids — Laws  of  Buoy- 
ancy elucidated — The  Importance  of  Stability, 
and  the  Laws  that  Govern  it. 

CHAPTER   II. 

An  Exposition  of  the  Tonnage  Laws — Their  dele- 
terious Effects — Necessity  of  Change — Tonnage 
Laws  of  other  Nations — Laws  of  Resistance — 
Laws  of  Propulsion. 

CHAPTER  III. 

Importance  of  a  Knowledge  of  the  location  of  the 
Centre  of  Effort — Method  of  obtaining  it — The 
Model,  an  American  Invention — Its  Advantages 
— Its  Origin — Its  complete  Adaptation  to  our 
Wants — Instructions  for  making  them. 

CHAPTER  IV. 

Taking  off  Tables — Their  Distribution  on  the  Floor 
— Sheer  Plan — Sheering  in  General — Its  Intimate 
Connexion  with  the  Appearance  of  Vessels. 

CHAPTER  V. 

Parallels  to  the  Line  of  Flotation,  commonly  called 
Water  Lines — Their  Effect  in  modelling — Half- 
Breadth  Plan — Body  Plan — Operations  on  the 
Floor  in  Laying  Off. 

CHAPTER  VI. 

Diagonal  Lines — Their  Use — Mathematical  Demon- 
strations in  Modelling  by  Diagonal  and  Water 
Lines,  discovered  by  the  Author-?— Their  Superi- 
ority over  the  Present  Mode. 


CHAPTER   VII. 

The  Author's  Discovery  in  obtaining  the  Centre  of 
Expansion — Its  importance  to  a  Proper  Distribu- 
tion of  the  materials  for  strength — Continued 
expositions  on  the  floor. 

CHAPTER  VIII. 

Cants  by  Water  Lines  —  Cants  by  diagonals  — 
Square  Stern,  without  stern  frame — Its  Advan- 
tages— Stern  Frame — Instruction  for  Building 
them — making  Moulds. 

CHAPTER    IX. 

Important  Rules  in  Practical  Operations — Direc- 
tions applicable  to  the  successive  stages  of 
Advancement  in  Building — Rules  for  Planking — 
Ceiling — making  Spars,  &c. 

CHAPTER  X. 

Steam-Boats — Ocean  Steamers — Coasting  Vessels — 
Vessels  Suited  to  River  Navigation. 

CHAPTER  XL 

Vessels  of  War  less  complex  in  their  Construction 
than  Merchant  Vessels — The  United  States'  Navy 
behind  the  age  —  Ships  of  the  Line  expensive 
and  inefficient — Frigates  and  Sloops-of-War — 
War  Steamers. 

CHAPTER  XII. 

Laws  of  Beauty  and  Taste — Heads  and  Sterns — 
Compend  of  all  the  Rules  for  Masting  and  Spar- 
ring vessels  of  all  descriptions — the  Author's 
improvements — Yachts. 


(52) 

l-VL 

© 


PREFACE. 


In  the  dedication  of  this  work  to  the 
Shipwrights  of  the  United  States,  the 
Author  has  no  apology  to  offer. 

However  much  may  have  been  pub- 
lished by  Naval  Architects  in  the  old 
world,  it  is  but  too  plain  to  the  think- 
ing mechanic  that  the  science  of  Ship 
building  is  yet  in  its  infancy. 

The  efforts  of  European  authors  to 
impart  such  information  as  shall  meet 
the  wants  of  operative  mechanics,  to 
qualify  them  for  the  responsibilities  of 
builders,  have  thus  far  proved  abortive 
both  in  the  old  and  new  world;  the 
reasons  are  obvious. 

The  very  limited  amount  of  inform- 
ation their  works  contain  upon  the 
branches  connected  with  the  merchant 
service,  in  connexion  with  their  com- 
plex character,  and  want  of  adaptation 
tothe  technical  terms  used  intheUnited 
States,  has  proved,  and  must  continue 
to  prove,  a  barrier  to  their  extensive 
circulation  in  this  country. 


Comparatively  few  American  me- 
chanics bury  their  talents  within  the 
walls  of  a  navy  or  dock  yard,  conse- 
quently, works  on  Naval  Architecture 
are  of  little  service  in  the  western 
world.  The  economy  of  our  govern- 
ment exhibits  the  utility  of  a  small,  but 
efficient  naval  force,  while  maritime 
enterprise  points  to  our  merchant  ships 
as  the  bulwark  of  her  defence.  To 
this  enterprise  we  are  indebted  for  the 
symmetry  and  efficiency  accredited  to 
American  ships  throughout  the  com- 
mercial world. 

This  work  is  designed  to  form  the 
connecting  link  between  science  and 
practice,  with  a  view  to  the  element- 
ary instruction  of  those  who  have  not 
previously  studied  the  principles  of 
science  in  modelling  and  building  ships. 

But  while  it  is  designed  as  the  novi- 
tiate's guide,  it  will  be  found  to  contain 
much  imformation  adapted  to  all 
branches  of  maritime  enterprise  ;   not 


PREFACE 


only  the  elementary  principles,  but  all 
the  departments  of  this  science  will  be 
distinctly  explained  and  illustrated  by 
plates  and  diagrams.  The  subject  of 
masting  and  sparring  vessels,  that  has 
been  considered  beyond  the  grasp  of 
scientific  men,  will  be  explained  in  its 
proper  department. 

Popularity  has  not  been  sought  at 
the  expense  of  science,  nor  brevity  by 
the  sacrifice  of  useful  information  and 
appropriate  illustrations.  The  work 
contains   not  a  few  original  improve- 


ments, and  it   is  confidently  ved 

that  it  will  n<>!   only  be  found 
body  in  all  departments,  the  latest  im- 
provements, but  to  be  in  advance  of 
the  age,  in  this  complicated  art. 

Finally, in  submitting  the  work  to  the 
judgment  of  the  mechanical  and  mer- 
cantile, community,  the  author  may, 
perhaps,  be  allowed  to  say,  that  he  lias 
left  no  means  untried  that  appeared 
likely  to  ensure  the  accuracy  and  ex- 
cellence of  the  work. 

JOHN  W.  GRIFFITHS. 


* 


MARINE  AND  NAVAL  ARCHITECTURE. 


CHAPTER    I. 

Early  History  of  Ship  Building — The  cause  of  its  Decline — Its  Revival  during  the  Middle  Ages — Reasons 
why  so  little  is  known  of  the  Art  from  History — Equilibrium  of  Fluids — Laws  of  Buoyancy  elucidated 
— The  Importance  of  Stability,  and  the  Laws  that  Govern  it. 


No  leaf  from  the  pages  of  antiquity 
can  contribute  so  much  towards  en- 
dowing posterity  with  a  correct  know- 
ledge of  the  race  of  man,  as  that 
which  narrates  the  progress  of  Science 
and  Art.  As  no  descriptive  exhibitions 
of  the  tree  equals  that  ot  its  fruit,  so 
no  expositions  of  the  workings  of  mind 
so  fully  develope  the  capacities  of  the 
inner  and  the  outer  man,  as  the  work 
of  his  hands.  In  scanning  the  musty 
folios  of  the  past,  it  would  seem  that  a 
second  deluge  had  swept  every  page  of 
the  history  of  mechanical  science  from 
the  face  of  the  earth.  Our  reductive 
energies  are  shackled  by  historians, 
who  have  delighted  to  luxuriate  on  the 
rise,  progress  and  ruin  of  their  race, 
while  the  most  prolific  mines  of  Science 
and  Art  have  been  left  unexplored;  the 
most  valuable  discoveries  to  the  com- 
mercial world  have  been  consigned  to 
the  incendiary's  torch, ordoomed  to  the 
tomb  of  Capulets  ;  the  exuberance  of 


language  has  been  exhausted  to  laud 
the  hero,  and  foster  a  spirit  of  military 
glory ;  the  bloody  riots  of  butchers 
of  their  race,  and  the  desolating  inarch 
of  tyrants,  have  been  narrated  with 
redundant  effusion.  The  irretrievable 
loss  of  information  respecting  the  pro- 
minent mechanics  of  early  ages,  may 
be  attributed  to  the  unsophisticated 
dogmas  of  such  men  as  Plato,  who 
poured  out  ebullitions  of  wrath  against 
his  followers  for  debasing  the  excel- 
lence of  geometry,  by  applying  it  to 
sensible  things.  Thus,  the  waves  of 
oblivion  cover  the  crumbling  temple 
and  its  builder  in  the  same  solitary 
grave.  The  baleful  shadows  of  the 
past  become  thick  and  impenetrable, 
like  the  midnight  of  Egypt ;  the  fluc- 
tuous  tide  of  time  leaves  only  the 
mound  between  the  furrows  on  its 
shores,  to  mark  the  spot  where  nations 
sleep.  Alas!  this  unsparing  scythe 
has  swept  over  the  glories  of  the 'past, 


10 


MARINE    AND    NAVAL    ARCHITECTURE, 


and  thus  we  road  the  fate  of  the  pres- 
ent. The  lover  of  antiquarian  know- 
ledge strains  his  eager  vision  in  por- 
ing over  the  musty  pages  of  the  past — 
he  looks  in  vain  to  find  anything  calcu- 
lated to  make  him  wiser,  surviving  the 
wreck  of  time.  The  philosopher  sighs 
and  mourns  over  the  desolation.  The 
man  of  science  weeps  as  he  looks  at 
the  almost  universal  blank.  The  agri- 
culturalist is  palsied  in  amazement  at 
the  silence  that  everywhere  reigns,  on 
the  subject  of  sustaining  animal  life. 
The  mechanic  is  led  to  exclaim  :  If  the 
past  can  furnish  no  wholesome  admo- 
nitions for  the  future,  let  it  perish  from 
the  recollection  for  ever  ;  let  the  man- 
tle of  oblivious  drapery  cover  its  crum- 
bling pyramids  and  solitary  graves  ! 
It  is  nothing  to  know  what  our  ances- 
tors were,  unless  it  be  accompanied 
with  the  desire  to  emulate  their  virtues 
and  avoid  their  errors.  What,  though 
the  mildew  of  mythology  coversthe  past; 
and  like  the  simoon  of  the  desert,  com- 
missioned to  obliterate  all  impressions, 
and  leave  one  wide-spreading  waste  ! 
But  our  Creator  has,  in  benevolence, 
as  in  wisdom,  adapted  our  mental  con- 
stitutions to  our  moral  responsibilities, 
and  permitted  us  to  weave  the  rainbow 
of  anticipation  on  the  dark  rolling 
clouds  that  overshadow  the  past.  How 
willingly,  when  thus  illumined,  do  we 
recur  to  periods  of  by-gone  greatness, 


and  throw  ourselves  on  the  bosom  of 
the  tempestuous  wave,  feeling  at  ease 
amid  boisterous  commotion,  as  one  re- 
lic leads  to  the  remembrance  of  an- 
other. It  is  thus  associations  become, 
in  our  hand,  a  golden  chain,  the  links  of 
which  lead  us  through  the  misty  laby- 
rinths of  commingling  thought,  to  the 
birth-place  of  their  existence.  When- 
ever we  attempt  to  penetrate  the  veil 
of  obscurity,  that  mantles  from  our 
view  the  work  of  ancient  mechanics, 
we  are  led  to  regret  that  some  one  of 
their  number  did  not,  for  the  sake  of 
posterity,  undertake  to  give  a  graphic 
description  of  the  state  of  mechanical 
science.  Many  learned  men  of  old 
deemed  it  the  part  of  wisdom  to  con- 
ceal in  mysticism  all  discoveries  in 
science.  This  custom  was  so  pre- 
valent at  one  time,  that  philosophers 
refused  to  leave  anything  in  writing  ex- 
plaining their  researches.  How  vast 
the  change  !  The  world,  in  modern 
times,  would  give  more  to  witness  the 
evolutions  of  the  Athenian  Ship-yard, 
than  to  witness  the  battles  of  all  the 
marshalled  armies  of  their  race. 

The  light  of  science,  mental,  moral, 
and  physical,  have  dispelled  the  gloom 
of  barbarism,  and  given  a  powerful 
impetus  to  man's  career,  down  to  the 
latest  future  in  the  vista  of  time. — 
Alas,  for  the  scruples  of  Plato  and 
his    coadjutors !     However    unwilling 


MARINE    AND    NAVAL    ARCHITECTURE. 


11 


some  few  shreds  of  ancient  mechanism 
have  found  a  conveyance  to  posterity, 
although  mingled  with  the  narration 
of  political  convulsions,  and  honored 
heroes  all  bathed  in  human  gore !  And 
though  the  relics  of  ancient  mechanism 
crumble  into  dust  with  the  weight  of 
centuries — the  hush  of  shipwreck  and 
the  briny  deep,  that  great  charnel- 
house  which  has  swallowed  up  millions 
of  our  race,  and  mantled  in  oblivion 
every  vestige  of  the  art  —  no  tower- 
ing pyramids,  or  massive  columns,  point 
generations,  yet  unborn,  to  the  skill  of 
their  ancestors ;  little  remains  above 
the  wide-spread  ocean  to  show  what 
was  the  form  of  that  engine  of  war,  or 
the  messenger  of  peace.  The  mytho- 
logical story  of  the  famous  Argonautic 
expedition,  by  Janos  and  his  compan- 
ions, seems  to  represent  the  result  of 
some  bold  commercial  expedition  after 
the  golden  fleece  of  Phyrxus,  that  far 
outstripped  all  the  previous  discoveries 
of  its  time,  by  which  Greek  maritime 
knowledge  was  extended  to  the  farthest 
shores  of  the  Euxine,  and  bears  a 
strong  resemblance  to  the  golden  expe- 
ditions of  the  present  time.  Little 
doubt  exists  of  the  Phoenicians  having 
been  the  discoverers  of  the  Art  of  Sail- 
ing ;  their  skill  in  evading  the  vigilance 
of  Nebuchadnezzar,  at  the  siege  of 
Tyre,  which  lasted  thirteen  years,  es- 
caping with  the  wealth  of  the   city  in 


their  vessels,  when  they  could  no  long- 
er defend  it ;  and  this,  too,  about  five 
hundred  and  seventy  years  before  the 
Christian  era,  shows  that  they  possess- 
ed more  than  a  superficial  knowledge  of 
commercial  pursuits.  The  great  naval 
victory  obtained  by  the  Greeks  over 
Xerxes,  (520  years  B.  C.,)  would  lead 
us  to  conclude  that  the  art  of  construct- 
ing vessels  was  known  and  practised  to 
a  considerable  extent,  more  particular- 
ly when  we  remember  that  Xerxes  had 
a  fleet  of  twelve  hundred  and  seven 
vessels,  each  capable  of  carrying  two 
hundred  and  thirty  men,  engaged  in  the 
combat.  The  very  fact  of  the  Grecian 
mariners  making  use  of  the  screw- 
pump,  introduced  by  Achimedes,  to  dis- 
charge water  from  their  vessels'  holds, 
would  lead  us  to  conclude  that  their 
vessels  were  not  mere  shallops,  as  those 
of  Europe  in  more  modern  times. 
Early  records  which  are,  doubtless, 
worthy  of  credit,  state,  that  when  the 
Chaldeans,  under  Nebuchadnezzar, 
conquered  Egypt,  they  struck  terror 
into  the  hearts  of  the  Egyptians,  at  the 
sight  of  their  vessels ;  this  was  five 
hundred  and  seventy-two  years  before 
the  Christian  era  ;  the  Egyptians  them- 
selves never  navigated  the  ocean,  being 
prejudiced  against  the  sea,  because  it 
swallowed  up  the  river  which  they  wor- 
shipped. Hence,  the  reason  why  they 
never  attempted  to  construct  vessels  of 


12 


MARINE    AND    NAVAL    ARCHITECTURE. 


any  considerable  size.      They  first  trav- 
ersed the  river  Nile  upon  rafts,  then  in 
the  canoe,  these  were  succeeded  by  the 
boat  built  with  joist,   fastened  together 
with  wooden  pins,  and  rendered  water- 
tight by  interposing  the  leaves  of  the 
papyrus ;  to  this  boat   was,  at  length, 
added  a  mast  of  Acanthus,  and  sail  of 
papyrus.      The  Phoenecians  were  a  na- 
tion nearly  as  ancient  as  the  Egyptians; 
situated  directly  on  the  sea,  without  the 
advantages  of  a  noble  river,  they  were 
compelled  to  provide  means  for  sailing 
on  a  wider   expanse   of  water.     It  is 
said,  however,  that  they  first  traversed 
the    Mediterranean,    and   even    visited 
distant  islands,  with  no  better  means  of 
conveyance    than    a    raft    of    timber. 
This  is  rendered  more  probable  from  the 
fact,  that  the  Peruvians,  even  in  mod- 
ern   times,     ventured    on    the    Pacific 
Ocean  on  their  balza,  a  raft  made  of  a 
spongy  tree  of  that  name.      The  vessels 
first    constructed   by  the    Phoenecians 
were   used    for   commercial  purposes : 
they  were  flat-bottomed,  broad,  and  of 
a  small  draught  of  water  ;   and  those  of 
the  Carthagenians   and    Greeks    were 
similar    in   shape.      By  successive    im- 
provements the  ships  of  antiquity  were 
at  length  brought  to  combine  good  pro- 
portions and  considerable  beauty.    We 
learn  from  Athenius,  that  Archimedes, 
that   illustrious  philosopher,  who  lived 
250  years  B.  C,  exhibited  a  skill  in  the 


art  of  building  ships,  that,  in  some  re- 
spects, is  scarcely  surpassed  at  the  pre- 
sent day.  A  ship  requiring  three  hun- 
dred men  one  year  to  build,  could,  by 
no  means,  have  been  considered  an  in- 
significant affair,  more  particularly 
when  we  are  told  that  she  had  three 
decks,  and  as  many  masts  ;  having  also 
an  engine  for  assaulting  purposes,  capa- 
ble of  throwing  stones  of  three  hundred 
pounds  weight  a  distance  of  two  hun- 
dred and  twenty  yards  ;  possessing,  also, 
engines  for  grapplhfg  with  the  enemy, 
and  guards  of  iron  to  prevent  them 
from  boarding  ;  the  stanchions  which 
supported  the  upper  deck  represented 
statues  of  Atlas,  nine  feet  long  ;  she 
was  fastened  throughout  with  copper 
bolts,  none  weighing  less  than  ten 
pounds  each  ;  on  the  middle  deck  were 
thirty  rooms,  in  each  of  which  were 
four  beds,  all  the  inventions  of  Arch 
medes  himself.  In  addition  to  the  force 
required  to  operate  her  engines  of 
death,  twelve  hundred  young  men  form- 
ed her  complement  for  operations.  The 
wonders  of  this  ponderous  fabric  were 
not  alone  exhibited  in  her  size  and 
powerful  armament, — her  baths,  gar- 
dens, conservatory  for  fish,  library, 
room  for  Venus,  the  Goddess  ofBeauty 
and  Love ;  in  addition  to  the  vari- 
ous embellishments  and  contrivances 
for  all  the  services  of  life,  her  ceilings 
represented  the  spangled  heavens  ;   she 


U 


MARTNE  AND    NAVAL    ARCHITECTURE, 


13 


had  a  single  screw  pump,  by  the  use 
of  which  one  man  could  pump  out  all 
the  water  that  leaked  into  her ;  she 
was  also  supplied  with  machines,  simi- 
lar to  our  forcing  pumps,  for  raising- 
water.  She  was  supplied  with  twenty 
ranges  of  oars,  and  twelve  anchors, 
eight  of  which  were  of  iron.  She  was 
named  the  Syracusan,  and  sent  as  a 
present  to  the  king  of  Egypt,  laden 
with  corn,  and  subsequently  named  the 
Alexandria. 

The  bows  of  vessels,  in  the  earlier 
ages,  were  denominated  the proic,  and 
ornamented  with  eyes,  as  those  of  the 
Chinese  at  the  present  time ;  and  in 
many  cases  decorated  with  sculptur- 
ed figures  of  heathen  deities,  and  other- 
wise adorned  with  paint  and  gilding, 
while  the  sterns,  which  were  usually  in 
the  form  of  shields,  were  elaborately 
wrought  in  carved  work,  (a  practice 
adhered  to  at  the  present  time.) 

The  vessels  first  used  for  war- 
like purposes  were  mere  row-boats, 
although  termed  ships-of-war.  They 
were  much  smaller  than  merchant 
craft,  and  rendered  so  for  convenience 
in  working  them,  in  which  the  combat- 
ants rushed  upon  each  other,  and  de- 
cided the  combat  by  valor  and  physical 
strength.  As  they  increased  in  size 
they  became  more  formidable,  and 
were  armed  with  an  iron  beak,  with 
which    the    contending    parties    often 


stove  in    the     sides    of    each    other's 
vessels. 

After  the  Phoenicians  discovered  the 
art  of  sailing,  all  their  vessels  were  pro- 
vided with  a  single  mast  that  could  be 
elevated  or  taken  down  at  pleasure ; 
they  were  also  provided  with  oars,  and 
thus  propelled  when  occasion  required. 
While  in  this  stage  of  advancement,  they 
were  stranded  at  the  termination  of 
every  voyage,  and  were  thus  drawn 
upon  the  shore  for  several  centuries, 
with  but  few  exceptions,  in  which  they 
were  too  large.  The  addition  of  a 
keel,  and  the  increase  in  size,  soon 
made  it  impracticable.  At  this  time 
sheet-lead  sheathing  came  into  use ; 
the  anchor  and  cable  came  in  for  their 
share  of  the  laurels  (about  the  same 
time)  with  which  to  decorate  the  brow 
of  the  inventor.  The  first  anchor  was 
nothing  more  than  a  large  stone ;  af- 
terwards wood,  and  finally  iron,  was 
the  sole  material.  Improving  in  size, 
as  in  other  qualities,  they  became 
about  as  large  as  what  was  subse- 
quently termed  galleys,  with  one, 
two,  and  three  banks  of  oars. — 
When  in  battle  the  combatants  con- 
tended above,  being  in  part  defended 
from  the  missiles  of  opposing  foes  by 
towers  and  screens  placed  on  deck, 
and  by  shields  carried  on  the  arm.  The 
approved  length  of  a  merchant  ship 
was  four  times  its  breadth,  while  those 


14 


MARINE    AND   NAVAL    ARCHITECTURE 


for  war  purposes  were  from  six  to  eight 
times  their  breadth.  From  these  pro- 
portions arose  the  distinction  of  long 
ships  and  round  ships,  or,  as  we  would 
transpose  the  term,  to  sharp  ships  and 
full  ships :  thus  we  discover,  that  the 
ancients, more  than  two  thousand  years 
ago,  knew  what  many  of  our  commer- 
cial men  have  yet  to  learn.  The  gene- 
ral size  of  merchant  ships  in  the  best 
days  of  antiquity,  was  not  greater  than 
that  of  our  sloops  and  schooners  ;  but 
there  are  instances  on  record  which 
prove  that  they  occasionally  equalled 
in  capacity  those  of  modern  times.  The 
destruction  of  commerce,  caused  by  the 
general  desolations  of  the  northern 
barbarians,  and  the  ruthless  incursions 
of  those  heathen  conquerors,  divert- 
ed the  channels  of  commerce  from 
their  legitimate  field  of  operation,  and 
caused  all  the  intercourse,  as  well  as 
the  expedition  of  a  warlike  character, 
to  be  conducted  on  land.  The  invasion 
of  the  Roman  empire  had  much  to  do 
with  causing  a  retrogression.  In 
some  parts  of  Europe  it  almost  extin- 
guished the  art  of  building  vessels: 
and  it  soon  dwindled  into  insignificance, 
and  thus  remained  until  the  middle 
ages,  when  the  active  trade  which 
arose  in  the  Mediterranean,  and  the 
naval  enterprises  connected  with  the 
Crusades,  occasioned  a  revival  of  the 
art.     Yet  it  did   not   advance  beyond 


the  condition  in  which  the  Carthage- 
nians  left  it,  until  the  middle  of  the 
fourteenth  century.  Alas,  for  the  com- 
mercial world  !  that  the  transcendent 
art  should  lie  amid  the  smouldering 
ruins  of  obscurity  ;  should  be  mantled 
with  the  drapery  of  blood,  for  nearly 
fifteen  hundred  years !  At  this  era  the 
inconsiderable  galleys  of  former  times 
began  to  be  superseded  by  larger  ves- 
sels, in  which,  however,  oars  were  not 
entirely  dispensed  with.  The  great 
change  in  the  general  construction  of 
vessels  arose  from  the  discovery  of  the 
polarity  of  the  magnet,  and  the  appli- 
cation of  astronomy  to  nautical  pur- 
suits ;  for  by  the  aid  of  these  means 
the  mariner  was  released  from  his  de- 
pendence on  the  sight  of  land  in  guid- 
ing his  vessel  on  its  course. 

To  the  Italians,  Catalans,  and  Por- 
tuguese, was  ship  building  mostly 
indebted  in  the  early  ages  of  its 
revival.  The  Spaniards  followed  up 
their  discovery  of  the  new  world  with 
rapid  improvements  in  both  the  form 
and  size  of  their  ships,  some  of  which 
have  been  rated  at  two  thousand  tons 
burthen.  In  more  modern  times  the 
French,  in  connexion  with  the  Span- 
iards, are  entitled  to  the  credit  of  near- 
ly all  the  improvements  which  have 
been  made  in  the  theory  of  the  art. 
Although  those  made  by  the  Eng- 
lish  have  been    of  some    importance, 


MARINE    AND    NAVAL    ARCHITECTURE. 


15 


yet  they  have  been,  and  are,  to  the 
present  day,  behind  the  age  in  many 
important  matters  pertaining  to  the 
art,  their  contributions  never  having 
been  commensurate  with, the  advantages 
they  possessed  for  advancement,  al- 
though the  greatest  naval  power  of  this 
or  any  other  time.  Her  narrow-mind- 
ed policy  in  this  branch  of  commercial 
enterprise,  causing  her  to  rear  restric- 
tive barriers  against  foreigners,  has 
proved  fatal  to  her  commercial  inter- 
ests. This  fatality  will,  doubtless,  be 
more  plainly  seen,  now  that  the  bul- 
warks restricting  her  intercourse  in 
navigation,  between  mother  and  daugh- 
ter, have  been  broken  down.  Its 
effects  are  but  too  manifest,  not  only  in 
her  works  on  ship  building,  but  in  her 
dock-yards  its  blighting  influence  is 
seen  and  felt,  like  mildew  in  every  de- 
partment of  hereditary  knowledge, — 
this  great  enemy  of  improvement. 

Foreign,  and  particularly  English 
authors,  have  frankly  admitted,  that 
there  are  abstruse  questions  connect- 
ed with  the  art  of  building  merch- 
ant ships  upon  the  principles  of  sci- 
ence, that  does  not  exist  in  the  con- 
struction of  vessels  of  war ;  and  with 
every  facility  afforded  them  in  Europe, 
they  almost  universally  announce  the 
art  of  building  ships  to  be  one  of 
analogies  and  comparisons.  Not  an 
author  has  dared  to  do  more  than  reite- 


rate the  hoary  traditions  of  their  an- 
cestors. The  commercial  world  has 
had  abundant  proof,  that  theory  with- 
out practical  knowledge  is  like  a  steam- 
boat without  an  engine,  a  steam  boiler 
without  fuel,  or  an  axe  in  the  hands  of 
the  man  who  has  not  learned  its  use. 
It  is  not  the  author's  province  to  induct 
American  mechanics  into  the  glories  of 
commerce,  the  great  engine  by  which 
the  blessings  of  civilization  have  been 
diffused  throughout  the  world ;  or  to 
linger  around  the  smouldering  portals 
of  antiquated  cities,  to  show  what  have 
been  the  advantages  of  commerce 
to  our  ancestors.  But  we  may  go 
back  a  distance  in  the  vista  of  time, 
only  commensurate  with  the  his- 
tory of  this  Republic,  and  view  the 
commercial  condition  of  Europe  and 
America.  Look  at  England,  whose 
national  policy  has  been  strictly  com- 
mercial; with  unbounded  resources  for 
inprovements,  the  canvas  of  whose 
ships  whitened  every  sea, — whose  pow- 
er and  influence  was  felt  in  every  clime  ! 
what  has  she  not  done  to  maintain  her 
supremacy?  She  abandoned  her  ton- 
nage laws,  and  adopted  another  code, 
calculated  to  give  an  impetus  to  her 
own  commerce,  and  at  the  same  time  to 
fetter  American  genius.  Failing  to  ac- 
complish her  designs,  she  sought  other 
fields  of  operations,  in  the  construc- 
tion of  Ocean    Steamers ;   learned,  in 


16 


MARINE    AND    NAVAL    ARCHITECTURE. 


1838,  that  which  Americans  had 
learned  more  than  twenty  years  pre- 
vious ;  and,  but  for  the  timely  assistance 
of  the  British  government,  the  enter- 
prise would  have  been  relinquished. 

Contrast  the  ebullitionsof  the  English 
press  at  the  successful  termination  of 
their  first  voyage  made  by  steam  across 
the  Atlantic,  with  the  history  of  steam 
navigation  in  the  western  world,  and 
the  contemplative  mind  will  be  con- 
strained to  regard  the  Anglo-Saxon  as 
a  working  rather  than  a  boasting  race. 
Scarcely  ten  years  had  elapsed  after  Ful- 
ton had  made  his  first  passage  to  Al- 
bany, by  the  aid  of  steam,  when  Ame- 
ricans were  ploughing  the  trackless 
deep  by  the  same  agency.  The  ocean 
steamship  Savannah,  as  she  approach- 
ed Cape  Clear,  was  reported  in  Liver- 
pool, by  telegraph,  to  be  a  ship  on  fire; 
and  His  Majesty's  cutter  was  sent  to 
her  relief.  Their  chagrin  and  amaze- 
ment may  be  imagined  at  the  discove- 
ry, that  with  all  sail  set,  in  a  fast  sailing 
vessel,  they  could  not  overhaul  this 
thing  of  life  under  bare  poles.  The 
prosecution  of  the  voyage  from  Liver- 
pool to  Copenhagen,  Stockholm,  St. 
Petersburgh,  Arendal  in  Norway, 
and  her  safe  return  to  the  United 
States,  at  once  solved  the  problem 
of  the  feasibility  of  navigating  the 
ocean  by  steam,  and  at  the  same  time 
exhibits  the    fecundity    of    American 


genius.  But  her  owners  had  learned 
something  more  than  the  mere  fact, 
that  it  was  possible  :  they  had  learned, 
that  steam  power  for  long  voyages  was 
unprofitable,  unless  endowed  with  cer- 
tain privileges  that  sailing  vessels  did 
not  possess.  Hence  the  reason  of  its 
abandonment,  until  our  government 
should  find  it  necessary  to  foster  the 
enterprise.  The  silent  footfall  of  time 
obliterated  from  the  public  mind  the 
sensation  produced  by  this  achievement, 
without  bombastic  eruptions. 

The  fact  is  too  palpably  plain  to  be 
for  a  moment  questioned,  that  Ameri- 
cans have  much  more  to  gain  by  ocean 
steam  navigation  than  other  nations. 
Hence  the  reason  why  all  Europe  ma- 
nifested so  much  surprise  at  the  tor- 
pidity of  Americans  in  embarking  into 
this  great  commercial  scheme.  The 
American  character  seems  to  be  but 
partially  known  abroad.  It  is  only  ne- 
cessary for  him  to  receive  an  affirma- 
tive answer  to  the  question,  icillit paif  I 
when  he  gathers  up  his  scattered 
thoughts,  and  concentrates  them  into  a 
single  idea,  or  into  the  compass  of  a 
telegraphic  despatch ;  and  then,  as  on 
wings  of  lightning,  he  is  ready  to  cir- 
cumnavigate the  globe,  or  to  embark 
in  any  enterprise  within  the  grasp  of 
thought,  or  the  conception  of  the  hu- 
man mind. 

What,  may  we   not  inquire,  is  the 


% 


MARINE    AND   NAVAL  ARCHITECTURE. 


17 


standard  value  of  American  ships 
abroad?  Is  it  not  universally  admitted, 
that  Americans  surpass  all  other  nations 
on  the  globe  in  the  superiority  of  their 
vessels  for  commercial  purposes  ? 

Let  us  now  turn  our  eyes  homeward 
and  see  what  can  be  done.      There  are 
few  of  our  prominent  ship-builders  in 
the  United  States,  who,  (under  a  judi- 
cious  code   of   tonnage  laws,)   do   not 
see  in  the  future  greater  improvements 
than  the  world  has  yet  witnessed.    We 
pause  to  inquire,    from   whence   have 
they  obtained  this  perspective   glance, 
the  outline  of  such  stupendous  improve- 
ments ?   The  casual  observer  may  have 
supposed,  from  works   on  naval  archi- 
tecture ;  but  let  one  of  their  number 
speak  for  himself,  and  before  introduc- 
ing   him,   let    me    add,  that    no   man 
upon  earth  enjoys  a  better  reputation 
as  a    practical  builder.     In  a  conver- 
sation upon   this   subject   with  David 
Brown,    he  said,  "it  has   always   ap- 
peared to  me  that  naval  architects  have 
done  all  they  could  to  mystify  the  the- 
ory   of    ship-building ;     subjects    that 
are  plain  have  been  rendered  intricate, 
and  costly  works  have  been  abandoned 
on  this  account."  Let  the  reader  decide, 
whether  science  without   practice,  or 
theory    and    practice    combined,     are 
most  likely  to  accomplish  the  work  of 
revolutionizing    the  commercial  world. 
The  genius  of  American    institutions 


has  imparted  an  indomitable  energy  of 
Herculean  power  to  her  favored  sons, 
that  surmounts  every  obstacle,  and 
knows  no  barrier.  The  boundless  fields 
open  on  every  side,  marking  no  dis- 
tinctive lines  of  birth  or  wealth  ;  but 
affording  genius  of  every  grade  an  op- 
portunity for  development,  and  its  con- 
sequent reward.  On  the  other  hand, 
it  must  not  be  supposed  that  energy 
alone  is  a  universal  Alcahest. 

The  prejudices  interwoven  with  the 
present  mode  of  modelling  ships,  cling- 
to  the  builder  like  the  poisonous  ivy  to 
the  monarch    of  the  wood,  binding  his 
thinking  powers  with  fetters,  which,  if 
not  rent   asunder,  will  cause  him,  like 
the    oak,  to    perish    in    their    palsying 
embrace.      The  streams  of  knowledge, 
connected    with    the    art    of    building 
ships  upon  the  principles  of  philosophy, 
have  been   poisoned  at  the    fountain. 
Rustic  and  philosopher,  sage,  sire,  and 
school-boy,  all  have  drunk  at  the  muddy 
pool.      The   hoary  head  of  prejudice, 
mantled  with  a    guise    of  experience, 
dams  up  the  streams  of  knowledge,  and 
hurls  defiance  at  the  man  who  dares  to 
assert    that    the    fields  of  science  are 
open  alike  to  all.     The  man  who  builds 
one  hundred  ships  by  the  same  model, 
contracted  or  expanded,  has    had  no 
more  real  experience    than  the    man 
who  has  built  but  one.     It  is  impossi- 
ble to  model  vessels  by  the  eye,  having 


18 


MARINE    AND    NAVAL    ARCHITECTURE 


no  reference  to  known  laws  that  gov- 
ern the  elements.  They  are  designed 
to  navigate  without  becoming  familiar- 
ized with  a  certain  shape  that  pleases 
us,  and  from  which  we  cannot  depart, 
that  every  ship-builder  is  fettered  with 
a  shape  peculiar  to  his  notion  ;  and  the 
ship  is  as  indelibly  stamped  with  lineal 
genealogy,  as  hereditary  lineaments  are 
visible  in  the  human  face. 

It  is  not  my  purpose  to  tax  the  read- 
er's forbearance  with  a  detailed  history 
of  the  discrepancies  of  the  present,  or 
to  draw  an  analysis  of  the  princi- 
ples that  has  governed  the  progress  of 
the  art,  as  recorded  on  the  historic 
page.  Were  we  thus  disposed,  we 
should  find  ourselves  encompassed  by 
the  trammelling  influence  of  prejudice, 
which  has  not  been  confined  to  the  old 
world,  but  has  been  transmitted  to  the 
shores  of  this  Republic,  and  has 
already  spread  over  a  surface  as  wide 
as  the  commercial  interests  of  our 
country. 

Science,  in  its  most  comprehensive 
sense,  may  be  classed  under  two  heads: 
a  knowledge  of  reasons,  and  their  con- 
clusions, constitute  abstract ;  that  of 
causes  and  their  effects,  and  of  the  laws 
of  nature,  natural  science.  Marine  ar- 
chitecture, or  the  art  of  building  ships 
upon  scientific  principles,  may  be  re- 
garded as  the  legitimate  offspring  of 
natural  science.     Hence  the  necessity 


of  a  knowledge  of  the  laws  governing 
non-elastic  fluids,  and  of  solid  bodies 
floating  on  fluids.  The  state  of  fluid- 
ity may  be  defined  as  that  property  in 
bodies  which  tends  to  form  drops  :  and 
this  property  does  not  exist  in  but  one 
of  the  three  states  in  which  matter  ex- 
ists, namely,  the  solid,  the  fluid,  and  the 
gaseous.  The  solid  may  be  reduced  to 
powder,  and  is  found  to  possess  no 
fluidity.  Some  writers  make  a  distinc- 
tion between  fluid  and  liquid,  confining 
the  latter  term  to  those  substances 
whose  particles  adhere  to  other  bodies 
plunged  into  them.  Thus,  mercury 
and  air  are  fluids,  but  not  liquids  ;  they 
leave  no  moisture  on  other  bodies  im- 
mersed in  them ;  while  water  and 
alcohol  are  both  fluid  and  liquid.  It 
may  be  remarked  here,  that  the  terms 
elastic  and  non-elastic  are  used  in  a 
relative  sense,  and  not  in  an  absolute; 
for  water,  and  probably  all  other  fluids 
of  the  same  class,  are,  to  a  certain  ex- 
tent, compressible  and  elastic,  though 
they  resist  compression  with  a  very 
great  force.  Writers  have  attempted 
to  give  mechanical  ideas  of  a  fluid 
body,  but  the  impossibility  of  giving  any 
kind  of  mechanical  comminution,  must 
appear  obvious,  if  we  but  consider  the 
circumstances  necessary  to  constitute 
a  fluid  body.  First,  that  the  parts, 
notwithstanding  any  compression,  may 
be  moved  in  relation  to  each  other,  with 


MARTNE  AND    NAVAL    ARCHITECTURE. 


19 


the  smallest  conceivable  force,  the ' 
particles  or  molecules,  (for  such  is  the 
distinctive  and  appropriate  term,  when 
applied  to  the  very  minute  parts  of  a 
fluid,)  yield  to  any  force,  however 
small ;  and  by  so  yielding  are  easily 
moved  among  themselves,  and  give  no 
sensible  resistance  to  motion  within 
the  mass,  in  any  direction.  Second, 
That  the  parts  shall  gravitate  to  each 
other,  whereby  they  have  a  constant  ten- 
dency to  arrange  themselves  around  a 
common  centre,  and  assume  a  spherical 
form,  which  is  easily  executed  in 
small  bodies,  inasmuch  as  the  parts  do 
not  resist  motion :  hence  the  appear- 
ance of  drops  always  takes  place  when 
a  fluid  is  in  proper  condition.  The 
dew-drop  stands  out  in  drastic  contrast 
with  solid  bodies,  similarly  circumstan- 
ced. Being  a  liquid,  it  must  of  neces- 
sity gravitate  towards  the  centre  ; 
hence  the  reason  of  its  globular 
form,  and  the  facility  with  which  the 
particles  may  be  moved  towards  each 
other.  It  will  be  perceived,  that  were 
it  possessed  of  the  inherent  properties 
of  matter  in  a  solid  state,  it  could  not 
be  raised  above  the  surface  of  a  vessel, 
or  heaped  up  in  a  spherical  form, as  the 
reader  may  have  often  witnessed.  So- 
lid bodies  can  by  no  means  conform  to 
these  conditions;  they  gravitate  down- 
wards, or  toward  the  centre  of  the 
earth,  while  a  fluid  body  may  be  divided 


and  subdivided  into  the  smallest  con- 
ceivable molecules,  and  each  particle 
will  adjust  itself  around  a  common 
centre.  This  independent  action  of 
fluid  bodies,  denominated  equilibri- 
um, is  a  property  which  has  perplexed 
not  only  the  mass  of  mankind,  but 
learned  men  in  every  age. 

From  what  has  been  shown,  it 
follows,  that  the  essential  difference 
between  fluids  and  solids,  consists  in 
the  equilibriated  gravity  of  the  for- 
mer, or  their  equal  pressure  in  all  di- 
rections— upwards,  downwards,  ob- 
liquely or  laterally.  The  whole  doctrine 
of  the  equilibrium  of  fluids  is  deduced 
from  this  fundamental  law. 

Whence,  if  any  particle  sustained  a 
greater  pressure  in  one  direction  than 
another,  it  would,  necessarily,  by  reason 
of  the  absolute  facility  of  motion,  and 
the  extreme  lubricity  with  which  it  is 
endowed,  give  way  and  move  towards 
that  part  where  the  resistance  is  least, 
and,  consequently,  there  would  be  no 
equilibrium.  One  of  the  obvious  con- 
sequences of  this  property  is,  that  its 
surface,  when  at  rest  in  an  open  ves- 
sel, and  acted  upon  by  no  other  force 
than  attraction,  is  horizontal  or  perpen- 
picular  to  the  direction  of  gravity  ;  if 
the  gravitating  forces  are  parallel, 
the  surface,  as  a  consequence,  will 
be  a  plane,  free  from  inequalities.  If 
they  tend  to  one  point  from  different 


20 


MARINE    AND    NAVAL    ARCHITECTURE. 


places,  or  all  converge  to  the  same 
point,  the  surface  of  the  liquid  will  be 
a  sphere.  Such  is  the  ocean,  bending 
away  from  a  perfectly  straight  line, 
eight  inches  in  every  mile ;  but  by 
reason  of  the  magnitude  of  the  sphere, 
the  curvature  of  any  small  portion  is 
imperceptible,  and  may  be  regarded  as 
a  plane.  The  pressure  of  a  fluid  on 
all  and  every  particle  of  the  vessel  con- 
taining it,  or  any  other  surface  in  con- 
tact with  it,  is  equal  at  the  same  alti- 
tude. From  this  proposition  it  obvi- 
ously follows,  that  the  pressure  on  the 
bottom  of  the  vessel  depends  entirely 
on  the  area  of  the  bottom  and  the 
depth  of  the  liquid,  and  is  entirely  inde- 
pendent of  the  force  of  the  sides,  and 
of  the  quantity  of  liquid  in  the  vessel. 
This  proposition  gives  rise  to  such 
results  as,  at  first  view,  appear 
most  absurd  ;  and,  as  a  consequence, 
has  been  termed  the  hydrostatic  par- 
adox, which  may  be  defined  on  a  larger 
scale,  sufficiently  comprehensible  to  an 
ordinary  mind.  A  column  of  water 
of  half  an  inch,  or  even  less  in  thick- 
ness, will  as  effectually  float  the  largest 
ship,  as  the  whole  ocean ;  and  abun- 
dant proof  of  this  is  afforded  at  every 
wharf  or  pier  at  which  vessels  are 
moored.  Vessels  are  there  seen  pre- 
serving an  equilibrium,  with  a  small 
column  of  water  on  one  side,  and  the 
river's  whole  breadth    on    the    other. 


The  appended  diagram  will  doubtless 
make  this  law  of  equilibriated  gravity 
in  fluids  so  plain,  that  further  exposi- 
tions will  be  unnecessary.  (See  Fig.  1.) 
It  is  the  altitude  that  determines  the 
pressure,  and  not  the  bulk.  It  will  be 
observed  that  the  diagram  represents 
the  water  at  the  same  height  on  both 
sides  of  the  ship.  AVithout  this  equili- 
brium the  ocean  would  be  of  no  ser- 
vice to  man  ;  vessels  might  be  built,  but 
they  never  could  be  sent  to  sea,  the 
preponderating  power  of  the  ocean  (be- 
ing the  largest  bulk)  pressing  upon  every 
coast,  and  upon  every  river  and  outlet, 
would  for  ever  lock  every  vessel  to  its 
native  shore.  Upon  this  principle  a  few 
ounces  of  water  may  be  made  to  sup- 
port any  weight,  however  great.  Many 
striking  phenomena  of  the  material 
world  are  deduced  from  this  principle. 
A  pipe  having  an  internal  surface  of  1 
foot,  or  an  interior  circumference  of  1 
foot,  or  4  inches  diameter,  the  area  of 
such  pipe  would  be  1  foot,  which  mul- 
tiplied by  1  foot,  or  12  inches  of  length, 
equals  144  square  inches.  If  such  pipe 
were  extended  140  feet  perpendicular, 
the  lower  section,  already  described, 
would  sustain  a  bursting  pressure  of 
8640  pounds,  which  is  about  equal  to  that 
produced  on  many  high  pressure  steam 
boilers.  A  column  of  water,  the  area  of 
whose  section  is  one  square  inch,  and 
of    which    the    height    is    27.727,    or 


MARINE    AND   NAVAL    ARCHITECTURE. 


21 


nearly  28  inches,  weighs  1  pound,  and 
28  inches  are  contained  60  times  in  140 
feet.  Hence  the  lower  end  of  the  pipe, 
1  foot  from  the  base,  must  sustain  this 
enormous  pressure,  because  144  inches, 
the  contents  of  the  foot  of  pipe,  multi- 
plied by  60,  gives  8,640  ;  and  this  pres- 
sure would  remain  unchanged,  however 
much  the  pipe  might  be  altered  at  the 
top,  while  its  perpendicular  height 
remained  ;  because,  while  the  altitude 
remained  the  same,  the  weight  of  a 
column  of  water  of  140  feet  in  length, 
1  foot  area,  is  pressing  upon  the  base, 
and  being  a  frictionless  body,  must  press 
with  the  same  weight,  even  though  the 
upper  139  feet  of  the  pipe  be  but  1 
inch  in  diameter.  If  a  farther  illustra- 
tion were  necessary,  it  might  be  obtain- 
ed in  witnessing  the  result  of  boring  a 
hole  in  the  bottom  of  a  ship  when  afloat, 
— we  at  once  see  the  fluid  ascend- 
ing with  a  pressure  proportionate  to 
the  area  of  the  hole.  If  the  fluid  did 
not  exert  a  pressure  upward  as  well  as 
downward,  it  would  be  a  difficult  matter 
to  account,  upon  philosophical  princi- 
ples, for  this  freak  of  nature.  It  will 
readily  be  perceived  that  the  atmos- 
pheric pressure  which  universally  cov- 
ers matter,  whether  solid  or  fluid,  has 
not  been  removed  from  the  ship's  hold, 
and,  as  a  consequence,  the  same  amount 
of  pressure  is  operating  upon  the  area 
of  the  aperture  that  is  exerted  at  the 


surface  of  the  fluid.  It  would,  doubtless, 
be  considered  superfluous  to  pursue 
these  illustrations  farther,  as  it  is  be- 
lieved the  subject  has  been  made  suffi- 
ciently clear  to  an  ordinary  mind.  Al- 
though water  is  a  body,  and  a  non- 
elastic  fluid,  yet  it  may  readily  be  de- 
composed, and  reduced  to  a  gaseous 
state.  It  is  a  curious  fact,  that 
notwithstanding  its  qualities  to  quench 
fire,  its  component  parts  (without  che- 
mical combination)  constitute  the  most 
combustible  and  explosive  compound 
known  ;  and  at  the  freezing  point, 
contains  140  degrees  of  latent  or 
secret  heat.  It  is  a  good  conductor  of 
sound,  and  is  entirely  free  from  friction- 
al  properties,  inasmuch  as  the  com- 
mingling influence  of  a  small  quantity 
of  the  fluid  poured  into  the  ocean,  af- 
fects all  the  water  therein  contained, 
and  sets  in  motion  every  particle  of  its 
enormous  bulk. 

Although  water  is  a  frictionless  body, 
and  at  all  times  maintains  an  equili- 
briated  surface,  and  cannot  be  lashed 
into  commotion  by  itself,  yet  we  see  it 
sometimes  threatening  to  rend  into 
fragments  the  boasted  representative  of 
man's  ingenuity  and  power.  It  is  the 
friction  caused  by  the  action  of  the 
wind  upon  the  surface  of  the  fluid  that 
causes  such  wondrous  results.  The 
casual  observer  would  be  led  to  con- 
clude,   that   the    equilibrium    of  fluids 


X 


•> 


22 


MARINE    AND   NAVAL    ARCHITECTURE. 


exists  only  in  the  brain  of  the  adherents 
to  this  dogma;  the  progression  of  the 
wave  would  appear  to  annihilate  every 
vestige  of  such  theory.     But   upon  a 
more  minute  examination  we  find  that 
the  wave  has  not  a  progressive  motion; 
when  the  fluid  is  set  in  motion  by  agi- 
tation, the  mass  is  not  transferred,  as 
will    appear  manifest    upon    observing 
any  light  body  upon  the  surface.     The 
appearance  of  progression  is  but  a  de- 
ception of  the  eye,  caused  by  the  form 
of  the  wave,  and  the  mode  of  its  oscil- 
lations.     By  close  attention  it  will  be 
seen  that  the  fore  part  is  always  in  the 
act  of  rising,  and  the  hinder  part  in  the 
act  of  falling  ;  and  thus  the  whole  mass 
appears  to  roll  onward,  while  each  par- 
ticle of  water  merely  oscillates  succes- 
sively, with  a  vertical  ascent  and  de- 
scent.   The  cause  of  this  reciprocating 
motion  may  be  thus  defined; — when  the 
surface  of  the  water  is  unequally  pres- 
sed by  the  wind,  the  columns  sustaining 
the   greatest   pressure   sink    below  the 
original  level ;  this  pressure  being  com- 
municated   to    the    adjacent   columns, 
causes  them  to  rise  above  the  level,  and 
this  lengthened  column  having  no  hy- 
draulic pressure  or  balancing  power  to 
sustain  it,  again  falls,  and  in  its  descent 
acquires  a  velocity  proportionate  to  its 
height,  descending  below  the  level,  and  in 
its  turn  communicates  a  pressure  to  the 
contiguous    columns.       Thus,    by   the 


particles  to  which  the  original  impulse 
was    given,    being    alternately    higher 
and  lower,  a  series  of  waves  are  form- 
ed, consequent  upon  the  force  and  un- 
equal   pressure  of  the  wind.     But   if 
this    free   oscillation  be  prevented   by 
shallow  water  or  rocks,  so  that  the  co- 
lumns in  deep  water  are  not  balanced 
by  those  in  the  shallow,  they  in  conse- 
quence acquire  a   progressive   motion 
towards  the  shallower  water  or  rocks, 
and  form  breakers :  hence  the   reason 
why  waves   always  break  against  the 
shore,  it  matters  not  what  is  the  direc- 
tion   of  the   wind.     It  has  been  often 
asked  why  so  much  damage  is  done  at 
sea,  if  the  waves   have  not  a  progres- 
sive motion?  This  is  partly  o\.  nig  to  the 
strength  of  the  wind,  r  nd  pa)  ly  to  the 
influence  of  the  pass^^  or  approach- 
ingvessel — the  side  ofthewave  present- 
ed to  the  wind  acquires  a  gentle  slope, 
while  the   opposite  or  lee  side  is  per- 
pendicular when  at  its  summit,  and  its 
own  weight  added  to  the  power  of  the 
wind,  while   the   balancing  column  is 
cut  off  by  the  proximity  of  the  vessel, 
causing    it   to  strike  with    destructive 
force.       The    progressive    wave     sent 
forward  by  a  vessel  in  motion  (or  gene- 
rated in  any  other  manner)  differs  en- 
tirely, not  only  in  its  character,  but  in 
its    phenomena,    from    the    oscillatory 
waves  of  the  ocean,  or  such  as   ripple 
the  surface  of  a  lake,  or  are  caused  by 


MARINE    AND   NAVAL    ARCHITECTURE. 


23 


the  sudden  elevation  or  depression  of  a 
small  portion  of  the  fluid.  It  does  not, 
necessarily,  arbitrarily  demand  a  de- 
pression or  elevation,  but  is  a  single 
elevation  of  a  well  defined  form,  and 
transferred  with  uniform  velocity  to  the 
contiguous  mass.  This  wave  is,  by 
Mr.  Russell,  said  to  be  analogous  to*  the 
tide  wave,  which  travels  at  the  rate  of 
1,000  miles  per  hour,  and  would  cir- 
cumnavigate the  globe  in  a  lunar  day. 
The  limits  of  this  work  prohibits  more 
than  a  cursory  glance  at  this  interest- 
ing subject.  The  reader  is  referred  to 
the  reports  of  the  British  Association 
of  1S38,  for  details.  The  author  does 
not  feel  free  to  occupy  a  space  com- 
mensurat:  /  witli  the  importance  of  in- 
vestigating subjects  that  do  not  imme- 
diately pertain  to  the  subject  before 
him ;  although  tne  cause,  formation, 
size,  anu  comparative  strength  of  the 
ocean  wave  is  a  subject  well  worthy  the 
attention  of  every  builder,  in  endeavor- 
ing to  approximate  the  resistance  to  be 
overcome,  and  the  power  he  possesses 
of  subduing  it. 

The  laws  of  equilibriated  gravity  in 
fluids  having  been  established,  the  buoy- 
ant property  of  the  fluid  will  be  next 
considered.  A  body  floating  in  a  fluid 
is  pressed  upward  by  a  force  equal  to 
the  weight  of  the  fluid  it  displaces  or 
sets  aside,  and  the  weight  of  the  entire 
body  is  exactly  equal  to  the  displaced 


bulk,  regardless  of  its  size  or  shape.  If 
the  specific  gravity  of  the  fluid  be 
greater,  the  body  will  displace  less,  be- 
cause a  smaller  bulk  is  equivalent  to 
the  weight  of  the  body ;  foi  example, 
a  ship  will  not  sink  as  deep  if  the 
water  be  salt,  as  though  it  were  fresh  ; 
nor  would  it  be  immersed  as  deep  at 
sea  as  in  a  fresh  water  river,  notwith- 
standing the  weight  of  the  ship  might 
be  precisely  the  same  in  both  cases.  If 
the  density  of  the  fluid  be  less  the  body 
will  sink  deeper,  because  a  greater 
bulk  of  the  fluid  is  required  to  com- 
pensate the  loss  of  weight  in  an  equal 
bulk ;  therefore,  in  all  cases  the  water 
displaced  by  a  floating  body  will  be  equal 
in  weight  to  that  body.  But  as  de- 
scribed in  a  former  hypothesis,  on  the 
constituent  properties  of  the  fluid,  it 
does  not  follow  that  a  smaller  bulk  of 
fluid  would  not  float  a  ship  ;  but  it  does 
follow,  that  however  small  the  column  of 
water  may  be,  the  altitude  must  remain 
the  same,  as  illustrated  by  the  diagram 
of  the  ship  at  the  pier  preserving  her 
equilibrium,  or  balanced  by  the  small 
column  between  herself  and  the  pier,  so 
that  there  must  be  a  line  of  immersion, 
or  a  line  of  flotation,  equivalent  to  the 
weight  of  every  floating  body  ;  but  the 
external  fulcrum,  or  line  of  flotation, 
remains  unaltered  only  under  the  fol- 
lowing circumstances,  viz. :  while  the 
weight  of  the  ship  remains  the  same, 


24 


MARINE  AND    NAVAL    ARCHITECTURE. 


and  the  fluid  remains  undisturbed, 
for  water  is  found  to  be  less  buoy- 
ant when  in  commotion  than  when 
at  rest.  Hence  the  reason  why  steam- 
boats careen  to  the  disturbed  side  when 
one  water-wheel  is  suddenly  revolved. 
It  will  appear  obvious,  that  when  the 
fluid  beneath  or  around  a  vessel  is 
disturbed,  from  whatever  cause,  in 
the  same  ratio  the  necessary  support  is 
drawn  from  the  vessel,  and  as  a  conse- 
quence, she  must  yield  to  the  side  thus 
disturbed.  This  is  apparent  from  two 
causes :  first,  the  pressure  on  the  un- 
disturbed side  is  the  greatest,  and  con- 
sequently the  preponderating  power 
must  be  felt ;  while,  by  disturbing  the 
fluid  we  take  away  a  portion  of  the 
support  required  to  sustain  the  weight, 
and  the  vessel  careens  until  she  finds  an 
equivalent  line  of  flotation.  It  is  from 
this  fundamental  law  that  the  weight 
of  all  floating  bodies  may  be  determin- 
ed :  the  weight  which  a  body  has  when 
wholly  immersed  in  a  fluid,  is  equal  to 
the  weight  of  an  equal  bulk  of  the 
fluid.  We  do  not  mean  by  this,  as  in 
the  case  of  the  body  partly  submerged, 
that  the  immersed  portion,  and  the  bulk 
of  displaced  fluid  are  equal  in  weight. 
In  the  case  of  immersion  it  matters  not 
whether  it  weighs  more  or  less  than  the 
fluid,  whether  it  be  cork  or  lead.  In  the 
case  of  lead,  it,  of  course,  woidd  sink, 
but  would  weigh  as  much   less  in  the 


water  than  in  air,  as  the  bulk  of  water 
it  displaced :  whereas  the  cork  would 
require  a  pressure  downward  to  sub- 
merge it,  equal  to  the  difference  of  its 
own  weight  in  air  and  a  bulk  of  water 
of  equal   magnitude.      If   this  weight 
were  applied  to  the  cork  it  would   be 
exactly  equipoised,  without  the  appli- 
cation   of  force.      When    it    is    stated 
that  a  body  loses  part  of  its  weight  in 
a  fluid,  it   must  not   be  supposed  that 
its  absolute  weight  is  less  than  it  was 
before,  but   that  it   is  partly  supported 
by  the  reaction  of  the  fluid  under  it,  or 
the  upward  pressure,  so  that  it  requires 
less    power    to  sustain   or   balance  it. 
This  proposition,  which  is  capable  of 
strict  demonstration,  may  be  also  illus- 
trated as  follows:  Suppose  any  interior 
portion  of  a  liquid  to  become  solid,  it 
would    evidently  remain    in    the  same 
state  of  indifference  or  equilibrium  as 
before.     It   must,  therefore,  be   borne 
up  by  the  vertical  pressure  of  the  fluid, 
with  a  force  just  equal  to  its  weight,  or 
which  is  the  same,  to  the  weight  of  the 
fluid,  whose  place  it  occupies  ;  and  if 
we    conceive    this   congealed  mass  to 
have  its  weight  increased  or  diminished, 
it  will  be  pulled  downwards  or  upwards 
by  the  difference  between  its  new  Aveight 
and  the  weight  of  an  equal  bulk  of  the 
fluid.     It  is  the  same  if  we  substitute 
any  solid  body  instead  of  this  block  of 
ice.     The  equilibrium  of  solid   bodies 


MARINE    AND    NAVAL    ARCHITECTURE. 


25 


floating  on  fluids,  is  an  important  part 
of  hydrostatics,  in  consequence  of  its 
relation  to  the  proper  construction  of 
ships.  The  laws  of  gravitation  teach  us 
that  all  solid  bodies  gravitate  toward 
the  surface  of  the  earth,  and  at  the 
same  time  have  a  central  point  within 
themselves,  which  is  so  situated  that  a 
line  or  plane  passing  through  the  body, 
and  cutting  at  the  same  time  the  cen- 
tre of  gravity,  whether  equally  or  un- 
equally dividing  them,  will  render  their 
weight  equal.  Hence  it  follows,  that 
if  the  centre  of  gravity  be  sustained, 
the  whole  body  will  remain  at  rest, 
whether  supported  from  beneath,  or 
sustained  from  above,  for  the  weights 
on  both  sides  of  this  vertical  plane,  or 
perpendicular  line,  passing  through  the 
line  of  support  or  centre  of  gravity, 
being  equal,  the  body  can  have  no  ten- 
dency to  angular  motion.  But  we  must 
distinguish  between  the  effects  of  grav- 
ity and  that  of  weight  ;  gravity  has  no 
dependence uponthe  mass, while  weight 
depends  entirely  upon  it.  For  exam- 
ple, in  a  vacuum,  or  a  reservoir  from 
which  air  has  been  extracted,  a  feather 
will  obey  the  laws  of  gravity  as  easily 
as  a  lump  of  lead ;  and  having  been 
started  from  the  top  at  the  same  time, 
would  also  reach  the  bottom  at  the 
same  time.  But  when  exposed  to  the 
atmosphere  we  find  that  by  reason  of 
the  density  of  the  lead,  or  the  bulk  of 


matter  it  contains,  or  its  excess  of 
weight,  that  it  falls  much  faster  than 
the  feather.  The  centre  of  gravitv  is 
an  imaginary  point  or  axis  ;  every  body 
has  a  centre  of  gravity,  and  so  has 
every  system  of  bodies.  It  is  not  al- 
ways within  the  body  itself;  the  cen- 
tre of  gravity  of  a  ring  is  not  in 
the  ring ;  neither  is  the  centre  of 
gravity  of  a  ship  in  the  materials 
of  which  she  is  built];  it  forms  no  part 
of  the  structure  itself,  and  yet  there 
can  be  no  structure  without  its  having 
this  central  point.  Thus  it  will  be 
perceived  that  the  centre  of  gravity  is 
an  imaginary  axis,  around  which  solid 
bodies  will  oscillate  when  circumscribed 
by  but  a  single  fluid,  or  wholly  immers- 
ed in  air,  water  or  any  other  fluid  ;  va- 
rying the  position  of  the  body  will  not 
cause  a  change  in  the  centre  of  gra- 
vity, since  any  such  change  will  be 
nothing  more  than  changing  the  direc- 
tion of  the  forces,  without  their  ceas- 
ing to  be  parallel ;  and  if  the  forces  do 
not  remain  the  same — are  increased  or 
diminished  as  the  body  approaches  or 
recedes  from  the  point  of  attraction; 
still  the  forces  upon  all  the  particles  of 
which  the  body  is  composed,  vary  pro- 
portionally, and  their  centres  remain 
unchanged.  If,  when  a  body  stands 
upon  a  plane,  a  vertical  or  perpen- 
dicular line  passing  through  the  centre 
of  gravity,    falls  within    the    base    on 


26 


MARINE    AND   NAVAL    ARCHITECTURE. 


which  the  body  stands,  it  will  not  fall 
over ;  but  if  the  vertical  line  foils 
without  the  base,  the  body  will  fall, 
unless  it  be  prevented  by  external  sup- 
port. When  the  vertical  line  falls  upon 
the  extreme  edge  of  the  base,  the  body 
may  stand,  but  its  equilibrium,  or  its 
stability  is  so  small  that  it  may  be  dis- 
turbed by  a  very  trifling  force, ..while 
the  nearer  the  vertical  line  falls  to  the 
centre  of  the  base,  the  more  firmly  will 
the  body  stand.  To  find  the  centre  of 
gravity  mechanically,  it  is  only  neces- 
sary to  dispose  the  body  successively  in 
two  positions  of  equilibrium.  This 
may  be  exemplified  by  particularizing 
a  few  methods.  Suppose  the  body  to 
be  the  model  of  a  ship  made  for  the 
purposes  of  calculations,  without 
screws  or  dowels,  as  in  all  cases  twin 
models  should  be  made,  where  accuracy 
is  required.  Insert  a  tack  in  the  sur- 
face of  the  plane  representing  the 
middle  line  near  the  extreme  point  of 
intersection  of  rail,  with  knight-head, 
from  which  suspend  the  model  by  a 
line,  hang  a  plummet  from  the  same 
point  of  suspension,  and  when  at  rest 
mark  the  intersection  of  the  line  with 
the  plane  or  straight  surface  of  the 
model ;  the  model  may  now  be  suspend- 
ed by  the  other  extremity,  representing 
the  intersection  of  the  rail  with  the 
stern;  when  suspended  from  this  point, 
a  plummet  may  be  hung  from  the  point 


of  suspension,  as  before,  and  its  inter- 
section with  the  surface  of  the  middle 
line,  and  where  the  line  crosses  the  for- 
mer plumb-line  of  suspension,  or  the 
point  of  intersection,  is  the  centre  of 
gravity,  as  in  fig.  2. ;  or  the  model  may 
be  suspended  by  two  lines  from  the  same 
point,  but  attached  to  different  parts  of 
the  model,  or  the  same  points  designa- 
ted in  the  first  example.  A  plummet 
suspended  from  the  same  point  will  fall 
on  the  centre  of  gravity.  In  this  ex- 
ample, if  the  lines  are  of  equal  length, 
the  centre  of  gravity  will  be  determin- 
ed longitudinally  only ;  but  having  as- 
certained its  longitudinal  location,  one 
of  the  lines  may  be  lengthened,  and  the 
operation  again  performed,  when  the 
plummet's  intersection  with  the  former 
lnarkwilldetermineitsaltitude:  seefig.  2. 
The  same  process  may  be  resorted 
to  in  determining  the  centre  of  buoy- 
ancy, by  separating  the  model  at  the 
load,  or  any  line  of  flotation,  below 
which  the  centre  of  displacement  is 
required,  as  in  fig.  3.  It  is,  doubtless, 
perfectly  clear  to  the  thinking  man, 
that  if  we  obtain  the  location  of  this 
point,  longitudinally  and  vertically,  that 
we  have  it  transversely,  inasmuch  as  the 
plane  surface  representing  the  centre  of 
the  vessel  transversely,  must  of  neces- 
sity confine  its  transverse  location  to 
that  plane,  as  the  exact  location  of  the 
centre  of  displacement  is  a  vastly  im- 


FIG.2.                           / 

^ 

\               "--..^ 

.— — -    / 

MARINE    AND    NAVAL    ARCHITECTURE. 


27 


port  ant  consideration  in  determining 
the  ratio  of  stability  the  vessel  may  pos- 
sess, and  is  the  only  index  for  the  pro- 
per location  of  the  engines  of  steam- 
ers. It  is  necessary  that  some  pains 
should  be  taken  in  determining  this 
point.  Its  location  may  be  found  on 
the  model,  without  knowing  the  actual 
amount  of  the  displacement,  or  the  ag- 
gregate bulk  of  water  displaced.  This, 
however,  may  also  be  determined  by  the 
model ;  but  when  the  draft  of  the  ship 
is  the  field  of  operations,  the  amount  of 
displacement  must  be  known,  to  locate 
its  centre,  and  this  can  only  be  known 
by  calculating  the  area  of  every  paral- 
lel section,  (to  the  line  of  flotation,)  or 
base  line,  according  as  the  sheer-plan 
may  be  disposed,  or  the  difference  in 
draught  of  water  be  determined  upon, 
whether  parallel  draught,  or  most  at 
the  stern.  When  the  buoyancy  is  so  ar- 
ranged that  the  vessel  will  draw  the 
greatest  draught  aft,  the  difference  is  in 
spacing  the  first  line  above  the  base  ; 
and,  as  a  consequence,  the  remaining 
ordinates  or  parallel  lines  should  be  equi- 
distant from  each  other.  Some  build- 
ers determine  the  longitudinal  centre 
of  displacement,  by  separating  the  mo- 
del, and  applying  the  edge  of  a  knife  or 
any  appropriate  instrument,  for  this 
purpose,  to  the  square  edge  of  the  sec- 
tion, with  its  surfaces  or  planes  in  a 
vertical  position,  the  edge  of  the  knife 


being  the  fulcrum,  either  the  section  or 
fulcrum  may  be  shifted  until  it  is  bal- 
anced, when  its  equilibriating  point  is 
noted  or  marked  on  the  middle  line  or 
square  edge  of  the  section.  This  me- 
thod is  adopted  with  each  section,  be- 
low the  greatest  immersed  line  of  flo- 
tation, when  the  mean  of  the  whole  is 
determined,  according  to  the  ratio  of 
the  bulk  of  each  section.  But  this 
method  is  objectionable.  Building  mo- 
dels, or  models  made  for  building  pur- 
poses, are  usually  screwed  together, 
without  reference  in  the  distribution  of 
the  screws  to  any  mechanical  method 
of  equilibriating  ;  and  mechanics,  in 
common  with  the  rest  of  mankind,  are 
easily  led  to  believe  what  they  wish  to 
be  true.  Hence  they  avoid  the  neces- 
sity of  making  a  model  facsimile  of 
the  first,  for  the  purposes  of  calcula- 
tions, or  twin  models,  as  they  are 
sometimes  called.  The  variation  in 
consequence  of  the  holes  for  the 
screws,  being  very  nearly  equally  dis- 
tributed, is  so  small,  that  it  will  furnish 
the  required  points  with  sufficient  ac- 
curacy for  all  practical  purposes.  It 
is  important  that  another  model  should 
be  made,  to  which  the  thickness  of  the 
plank  should  be  added  ;  it  may  be  glued 
together  as  high  as  the  load-line  of  flo- 
tation,  at  which  line  it  should  be  left 
free  for  separation ;  the  top-side,  or 
the  section  above  the  line  of  immersion, 


28 


MARINE    AND    NAVAL    ARCHITECTURE. 


may  also  have  the  thickness  of  the 
plank  added,  and  its  several  sections  or 
shear  pieces  glued  together.  When  the 
several  methods,  already  described,  for 
obtaining  the  centre  of  gravity  and 
centre  of  displacement,  or  the  centre 
of  gravity  of  the  displacement,  are  con- 
ducted with  care,  the  location  deter- 
mined is  sufficiently  reliable  for  any  and 
every  practical  purpose.  There  are 
several  methods  of  obtaining  the  dis- 
placement, or  the  actual  bulk  of  water 
displaced  by  a  vessel,  two  of  which 
only  are  necessary.  The  first  is,  with 
the  aid  of  the  model,  in  which  case  a 
box  made  of  some  material  that  will 
not  absorb  the  water ;  the  box  should 
be  made  by  such  dimension  as  will  en- 
sure the  immersion  of  the  model.  At 
one  end,  near  the  top,  (which  should  be 
open)  a  facit  may  be  inserted,  and  at  the 
bottom,  on  the  inside  of  the  box,  a 
small  pulley  may  be  fastened,  through 
which  a  horse-hair,  or  some  very  fine 
line  may  lead  to  the  top,  sufficiently 
long  to  fasten  one  end  to  the  model, 
while  the  other  end,  leading  through  the 
pulley,  will  come  above  the  top  of  the 
box.  A  nice  pair  of  balances  should 
now  be  prefixed,  having  a  concave 
scale  at  one  or  both  ends  of  the  beam, 
sufficiently  large  to  contain  a  bulk  of 
water  equal  to  the  bulk  of  the  model, 
and  adjusted  with  one  scale  immediate- 
ly under  the  facit  and  having  the  appro- 


priate weights  at  hand  ;  the  box  may 
now  be  filled  with  pure  rain  or  distilled 
water,  as  high  as  the  facit  will  allow 
without  leakage  ;  the  model  should 
be  suspended  by  the  line,  and  carefully 
lowered  into  the  box  until  it  finds  its 
balance  in  its  buoyant  properties,  when 
the  end  of  the  line  leading  through  the 
pulley  may  be  slowly  taken  in,  until  the 
model  is  immersed,  as  in  Fig.  4,  when  it 
will  be  found  that  a  bulk  of  water,  ex- 
actly equal  to  the  model  which  repre- 
sents half  of  the  immersed  portion  of 
the  vessel,  is  deposited  in  the  scale  un- 
der the  facit.  The  water  may  now  be 
weighed,  and  the  displacement  readily 
computed  in  the  following  manner : 
For  the  sake  of  convenience  we  have 
assumed  the  model  to  have  been  made 
upon  a  scale  of  3S.4  of  a  foot,  or 
when  the  foot  is  divided  into  inches, 
eighths  and  sixteenths,  it  would  be  re- 
cognized as  being  ~,  or  one  quarter  and 
one  sixteenth.  The  reason  for  adopting 
this  scale  for  the  elucidation  of  this 
subject,  is  simply  because  it  divides  the 
cubic  foot  into  64,000  cubes,  or  cubic 
feet,  represented  in  the  model,  each  of 
which  equals  in  bulk  7.5,  or  7| 
grains  of  distilled  water.  By  this  hy- 
pothesis we  have  but  to  know  or  as- 
sume the  weight  of  the  bulk  of  water 
forced  out  of  the  box,  and  the  tonnage 
is  at  hand  ;  assuming  the  bulk  to  be 
160  ounces,  we  have  this  formula. 


MARINE  AND    NAVAL    ARCHITECTURE. 


Grains.  Cubic       Pounds  Pounds 

Oz.        Grains,      per  ft.      feet.  per  ft.       Pounds.        per  ton.    Tons.        Pds.  Tons.       Pds. 

160=76,8004-7.5=  10,240x62.5=640,0004-2,240=285+  1,600x2=571+960 


Thus  it  is  plain,  that  the  displace- 
ment of  one  half  of  the  vessel  equals 
285  tons,  1,600  pounds,  while  the  en- 
tire displacement  of  both  sides  equals 
571  tons  and  960  pounds ;  it  must  be 
remembered  that  this  is  the  weight  of 
the  vessel  and  cargo,  when  loaded  to 
the  greatest  immersed  line  of  flotation, 
and  not  the  weight  of  the  vessel 
alone,  if  it  were  built  of  such  mate- 
rial, that  its  specific  gravity  and  that 
of  the  model  were  alike,  or  the 
same,  then  the  weight  of  the  vessel 
could  be  determined  by  allowing  the 
model  to  float  in  the  box,  with  the  top 
side  annexed,  and  the  bulk  of  water 
forced  into  the  scale  would  denote  the 
weight  of  the  vessel  by  the  same  for- 
mula as  has  already  been  described. 
The  laws  of  displacement  are  plain  and 
easily  understood.  Every  vessel  dis- 
places an  amount  of  water,  the  bulk  of 
which  is  of  sufficient  weight  to  com- 
pensate, or  to  equilibriate  the  weight 
of  the  vessel,  and  the  difference  be- 
tween the  lines  of  flotation  that  com- 
pensates the  weight  of  the  vessel, 
(sometimes  called  the  launching  line  of 
flotation)  and  the  greatest  line  of  im- 
mersion is  the  displacement  or  bulk  of 
water  set  aside  by  the  cargo  and  stores, 
or  whatever  is  put  on  board  the  vessel 
after  the  launching  line   is  taken.     It 


will  be  found  that  there  is  a  discrepan- 
cy in  the  calculation,  if  the  cargo  is 
weighed  and  compared  with  the  dis- 
placement noted  down  at  the  several 
lines  of  flotation.  This  arises  from  the 
difference  in  the  specific  gravity  of  the 
water  used  in  the  hydrostatic  balance, 
and  that  in  which  the  vessel  floats. 
Distilled  or  pure  rain-water  has  been 
regarded  as  an  invariable  standar^when 
under  the  same  weight  of  air ;  hence 
the  reason  for  selecting  it.  But.  the 
water  in  our  rivers  is  variable  in  its 
weight,  or  its  specific  gravity.  It  is 
well-known  that  although  water  is  a 
non-elastic  fluid,  (speaking  in  general 
terms)  yet  it  is  capable  of  containing 
accessions  from  the  mineral  kingdom, 
without  increasing  its  bulk,  although 
its  specific  gravity  is  augmented  in  pro- 
portion to  the  density  and  quantity  of 
such  increase.  As  has  been  already 
stated,  the  fluid  being  composed  of  in- 
finitely small  particles,  of  spherical  or 
globular  form ;  it  is  thus  cavities  are 
formed.  A  glass  may  be  filled  with 
water  until  it  will  contain  no  more,  yet 
it  will  be  found  sufficiently  capacious 
to  contain  sugar,  alum,  and  salt. 
Hence  it  is  clear  that  water  may  differ 
in  its  specific  gravity,  and  that  the  less 
pure  the  more  dense  or  greater  its 
weight.      And  that  it  weighs   less   in  a 


30 


MARINE    AND    NAVAL    ARCHITECTURE. 


state  of  purity  than  in  any  other  state. 
In  the  exposition  of  the  method  of  ob- 
taining displacement  by  the  aid  of  the 
hydrostatic  balance,  we  have  set  down 
its  specific  gravity,  when  in  a  state  of 
purity,  at  1,000  ounces,  while  the  mean 
specific  gravity  of  sea-water,  according 
to  the  experiments  of  the  late  Dr. 
Marcet,  was  found  to  equal  1.02777, 
near  the  equator.  We  are  also  inform- 
ed that  there  is  no  notable  difference 
between  sea-water,  under  different  me- 
ridians. Perhaps  a  homely  illustra- 
tion of  some  every-day  occurrence  may 
serve  a  better  purpose  than  any  other 
that  I  might   be  able  to   adduce.     We 


may  have  often  seen  a  full  measure  of 
apples,  and  although  no  more  could  be 
pressed  into  the  measure,  yet  it  would 
contain  various  kinds  of  grain  ;  and 
when  thus  doubly  filled  with  apples  and 
grain,  it  would  hold  water  in  addition 
to  what  it  already  contained  :  so  with 
the  fluid  itself.  The  vessel  will  be 
found  to  draw  less  water  at  sea  than 
the  balance  indicated  ;  hence  the  ne- 
cessity of  an  addition  to  the  weight  of 
the  fluid,  which  is  found  to  equal  about 
3  per  cent.,  or  one-thirtieth  of  its 
weight  in  solid  matter,  the  bulk  of 
which  is  chiefly  salt.  Thus,  in  the  for- 
mula, instead  of 


Pds.  per 
Ton.      Tons. 


Pounds.  Ton.      Tons.  Pds.         Tons.        Pds. 

640,000-^2,240,  we  have,  640,000+19,200=659,200-=- 2,240=294  +  6402  =  588  +  1280 

Or,  the  formula  may  be  thus  : 

Pounds.  Tons.     Pds.  Tons.       Pds, 

„, 640,000x3 

640,000+ — -L_ =  659,200-^2,240=294+640  x  2=588+ I2S0 

This  additional  weight  will  not  be  ne- 
cessary for  the  navigation  of  our  lakes, 
although  the  use  of  the  hydrostatic  bal- 
ance is  one  of  the  most  efficient  and 
reliable  modes  of  determining  the 
amount  of  displacement  from  the  mo- 
del, unless  by  actual  computation,  which 
exacts  a  tax  of  time  which  few  builders 
are  willing  to  submit.  There  are  other 
modes  of  facilitating  the  work  that 
air.  perhaps,  worthy  of  our  attention  ; 
a  box  may  be  made,  as  in  the  former 
case,  without  reference  to  its  contents, 


of  a  material  that  will  not  absorb  the 
fluid,  with  a  facit  in  its  end,  and  a  pulley 
arranged,  as  in  the  former  case.  An- 
other box  should  also  be  prepared,  of 
the  same  material,  the  internal  contents 
of  which  may  be  known,  as  follows  :  A 
box  in  the  form  of  a  cube  of  1.05 
inches,  will  contain  64  cubic  feet,  or 
2.5  will  contain  512  cubic  feet,  or  a 
cube  of  5  inches,  will  contain  4.096 
feet,  we  have  assumed  the  scale  to  re- 
main unchanged,  as  in  the  first  exam- 
ple of  the  hydrostatic   balance.     The 


MARINE    AND    NAVAL    ARCHITECTURE. 


31 


box  itself  in  which  the  model  is  im- 
mersed may  be  thus  apportioned  on  its 
sides,  by  marking  the  scale  of  contents 
in  the  ratio,  as  given,  and  the  displace- 
ment may  be  determined,  without  far- 
ther trouble,  by  the  computation  of 
cubic  feet  into  tons,  as  per  example, 
assuming  the  box  to  have  an  area  of 
5x1  (feet,)  then  we  have  this  formula, 
5  feet  of  length  =50  feet  per  scale,  1 
foot  of  breadth  =10  feet  per  scale  : 
thus,  50x10=500.  Then  we  have,  for 
every  ^6  of  height  in  the  box,  500  cu- 
bic feet.  There  are  two  other  meth- 
ods of  determining  the  amount  of  dis- 
placement, one  by  comparative  bulk, 
the  other  by  comparative  weight.  As- 
suming the  model  to  be  made  of  mate- 


rials, the  specific  gravity  of  which  is 
known,  a  block  of  the  same  material, 
and  of  the  same  specific  gravity,  in  the 
form  of  a  cube  of  5  inches,  which,  by 
the  last  example,  contains  4,096  cubic 
feet  ;  and  assuming  the  specific  gravity 
to  be  equal  to  that  of  distilled  water, 
both  that  of  the  model  and  block  we 
have  the  following  :  If  4  pounds  =the 
weight  of  the  block  containing  4,096 
cubic  feet,  what  will  be  the  contents  of 
the  model,  assuming  the  model  to  weigh 
16  pounds.  Thus  we  have  the  same 
results  as  before :  4  pounds  weight  of 
block  contain  4,096  cubic  feet,  what 
are  the  contents  of  10  pounds,  the 
weight  of  the  model? 


Block 

4,096  X   10 


Contents 
Weight  in  feet  of 
of  model.       block.        Pds, 


Pds.  per 
foot. 


Cubic  ft.  foot.  Pounds.        Ton.  Tons.        Pds.  Tons.        Pds. 

40,060  -v-  4  =  10,240  X  62.5  =  640,000^-  2,240=285+1,600  x  2=571+960 


To  this  add  the  difference  between  distilled  and  salt  water,  19,200  pounds, 
and  we  have, 


640,000  +  19,200  =  659,200  4- 

Thus  we  have  the  same  results  as  be- 
fore. There  is  another  method  that  is 
sometimes  adopted ;  but  as  it  is  liable 
to  variations,  and  subjects  the  prac- 
titioner to  error,  unless  the  most  rigid 
scrutiny  is  observed  throughout  the 
operation  ;   and  even  under  this  test,  I 


2,240 


Tons.     Pds. 

=  294+640  x  2 


Tons.       Pds. 
=  588+  12S0 


the  second  example  of  the  hydrostatic 
balance,  with  this  exception,  the  me- 
dium is  sand  instead  of  water.  Having 
prepared  the  two  boxes,  as  in  the  case 
alluded  to,  we  shall  require  a  bulk  of 
sand  sufficient  to  fill  the  box,  free  from 
moats    and   every   other   impurity.      It 


should  only  deem  it  safe  where  an  ap-    should   be   also    perfectly  dry,  and  the 


proxiination   was    all  that    I  required. 
Tin;  mode  alluded  to  has  a  similarity  to 


entire     cubical    contents   of    the    box 
known.      After  which  it  may  be  filled, 


32 


MARINE    AND    NAVAL    ARCHITECTURE 


with  moat  care,  through  a  sieve  would 
be  the  preferable  mode,  as  sand  is  to 
some  extent  like  grain,  and  will  settle  in 
a  smaller  compass  readily  ;  the  box  be- 
ing filled,  the  surplus  above  the  edges 
may  be  carefully  stricken  off  with  the 
straight-edge  or  ruler.  The  surplus 
should  now  be  removed,  and  a  large 
cloth  spread  to  receive  the  sand  from 
the  box,  which  being  empty,  is  ready 
for  that  part  of  the  model  below  the 
load-line,  or  line  of  immersion.  If  the 
model  cannot  be  separated  without  in- 
jury, the  surface  representing  the  mid- 
dle line  may  be  placed  against  the  side 
of  the  box,  the  load-line  at  the  same 
time  cutting  the  edge  of  the  box.  Thus 
having  the  immersed  portion  in  the  box, 
and  emerged  part  out,  when  this  me- 
thod is  taken,  the  box  may  be  made  of 
wood,  and  the  sides  and  edges  must  be 
perfectly  straight.  The  model  having 
been  adjusted  in  the  box,  the  sand  may 
now  be  put  in,  as  before.  Particular 
care  should  be  taken  that  the  methods 
of  filling  the  box  should  be  alike  in 
both  cases, — being  filled  to  the  edge, 
and  stricken  off  by  the  edge  on  the 
box,  and  load-line  on  the  model.  The 
surplus,  or  that  portion  of  sand  the  box 
will  not  contain,  may  now  be  measured 
by  the  small  box  prepared  for  the  pur- 
pose ;  as  in  the  second  example  of  the 
hydrostatic  balance.  Assuming  the 
model  made  for  those  several  modes,  to 


be  made  by  the  same  scale,  ~  of  an  inch, 
a  box  of  five  inches  square  will 
contain  4,096  cubic  feet  ;  while  on 
an  inch  scale,  or  ±  of  the  foot,  the 
box  will  contain  but  125  cubic  feet. 
Thus  the  importance  will  be  readily 
discovered,  of  continuing  to  adopt  the 
scale  with  which  we  begin  our  compu- 
tation. Some  may  have  supposed  that 
the  scale  upon  which  a  model  is  made 
should  be  without  any  fractional  parts. 
And,  as  a  necessary  consequence,  it 
may  be  more  readily  understood.  But 
I  have  never  been  able  to  discover  such 
advantage.  Whenever  calculations  are 
to  be  made,  it  is  certainly  much  more 
convenient  to  deal  in  round  numbers  ; 
and  to  do  this  we  may  divide  the  foot 
into  tenths ;  the  scale  assumed  is  a 
small  fraction  more  than  the  $  of  a 
foot  :  and  to  divide  the  foot  into  40 
equal  parts,  would  be  the  correct  mode 
of  proceeding,  as  it  will  be  discovered 
that  were  a  sufficient  number  of  x|  ad- 
ded together,  we  would  not  find  the 
scale  to  be  the  exact  ratio,  as  40  times 
a  would  make  121  inches ;  but  having 
adopted  this  scale  as  approximating  the 
nearest  to  the  scale  in  general  use  ;  and 
at  the  same  time  a  very  near  approxi- 
mation to  the  truth,  it  was  deemed 
prudent  to  adopt  the  course  as  better 
calculated  to  illustrate  the  leading  prin- 
ciples, than  another  scale  that  could  not 
be  found  marked  on  the  rule  in  genera] 


. 


MARINE    AND    NAVAL    ARCHITECTURE. 


33 


use.  It  may  be  well  to  remark  further, 
that  in  making  models  to  build,  or  to 
make  calculations  from,  it  is  always 
best  to  make  a  scale  on  a  slip  of  paper, 
and  if  the  practitioner  is  not  sufficient- 
ly skilled  in  the  use  of  the  drawing- 
pen,  he  would  realize  the  time  well 
spent  in  learning  its  use.  When  we 
have  lost  the  scale  by  which  a  model  is 
made,  the  model  is  of  no  use  unless  the 
scale  is  known.  Thus  we  have  the 
key,  and  no  man  can,  without  much 
difficulty,  make  use  of  the  model  or 
drawing,  without  this  key.  It  will  be 
readily  discovered,  that  if  the  scale  is 
altered  after  the  model  is  made,  that  it 
disproportions  the  vessel;  and  that  by 
departing  from  the  dimensions  we  lose 
the  shape.  For  example,  if  the  scale 
be  increased  from  ~  to  ~,  or|,  (the  scale 
in  general  use)  we  diminish  the  size  of 
the  vessel.  But  this  is  not  all;  we  alter 
the  principal  dimensions,  and  thus,  by 
increasing  the  scale,  we  diminish  the 
size  of  the  vessel ;  and,  by  diminishing 
the  scale,  while  the  model  remains  the 
same  size,  we  increase  the  size  of  the 
vessel.  A  vessel  100  feet  long,  25  feet 
wide,  and  12ifeet  deep,  by  the  scale  we 
have  assumed  in  our  foregoing  exam- 
ples, jj,  would  measure,  by  an  increase 
of  the  scale  to~,  or  |,  S3  feet  4  inches 
long,  20  feet  8  inches  wide,  and  10  feet 
4  inches  deep,  while,  by  reducing  the 
scale  to  -5,  ir  \  of  an  inch,  we  have  the 


vessel  increased  to  125  feet  long,  31 
feet  wide,  and  15ifeet  deep.  Thus,  it 
will  be  readily  discovered,  that  the 
scale  is  to  the  model,  what  the  key  is  to 
the  lock ;  and  if  we  adopt  another 
scale  we  alter  the  model  or  shape  of  the 
vessel.  It  does  not,  however,  follow 
that  a  scale  cannot  be  made  to  answer 
the  purposes  of  expanding  and  con- 
tracting models  or  draughts,  and  yet  re- 
tain the  shape  and  proportionate  di- 
mensions. This  can  be  accomplished, 
and  will  be  fully  explained  in  its  proper 
place. 

There  is  yet  another  mode  of  deter- 
mining the  displacement,  by  the  use  of 
the  model  separated  at  the  line  of  im- 
mersion. And  if  this  mode  be  deemed 
preferable,  reference  should  be  had  to 
it  when  the  model  is  made,  which 
should  be  glued  together.  In  the  se- 
lection of  materials  for  the  model, 
enough  should  be  reserved  out  of  the 
middle  of  the  board  to  make  a  water- 
line  section,  as  shown  in  the  appended 
diagram,  Fig.  5.  It  will  be  observed, 
that  although  this  mode  of  operation  is 
denominated  coinjxirativc  weight,  yet  it 
depends  materially  upon  the  specific 
gravity  of  the  material.  Hence  the 
necessity  of  selecting  all  the  pieces  of 
which  the  block  is  composed,  from  the 
middle  of  the  same  board  of  which  the 
ends  are  taken  for  the  model,  the  top 
end  of  the  board  forming  one  length  of 


34 


MARINE    AND   NAVAL    ARCHITECTURE. 


water-line,  and  the  butt-end  another, 
the  middle  being  the  block,  would  be 
the  mean  density  of  the  board.  It  will 
also  be  observed  by  the  diagram,  that 
the  pieces  are  equal  in  thickness,  and 
precisely  the  same  as  those  of  the 
model.  And  this  being  the  case,  it  is 
only  necessary  to  determine  how  many 
cubic  feet  is  equal  to  the  required  dis- 
placement, (remembering  that  the 
number  of  water-line  pieces  and  the 
depth  of  the  block  compare  exactly 
with  the  depth  of  the  model.)  Having 
thus  ascertained  the  number  of  feet  re- 
quired to  equal  half  the  displacement, 
or  half  the  model,  it  remains  to  reduce 
the  block  to  its  equivalent  size.  In 
the  example  given  in  the  diagram,  the 
depth  of  the  model  is  twelve  feet,  as  is 
also  the  block.  Thus  we  discover  that 
the  half  model  contains  S49  tons  1,920 
pounds ;  or  the  block  equals  a  bulk  of 
water  which  would  weigh  that  amount; 
and,  as  the  model  is  of  equal  weight, 
contains  the  same  amount  of  tons. 
As  we  have  thus  given  all  the  available 
modes  of  determining  the  displacement 
from  the  model,  we  shall  next  inves- 
tigate the  manner  of  accomplishing 
the  same  from  the  draught.  Few 
vessels  are  built  in  the  United  States 
from  the  draught  ;  and,  as  a  con- 
sequence, ship-wrights  in  general  are 
unacquainted  with  its  advantages  in  ob- 
taining the  ratio  of  stability,  expansion, 


&c.  Hence  one  of  the  reasons  why  the 
draught  is  repudiated  by  the  casual  ob- 
server. In  calculating  the  amount  of 
displacement,  or  the  number  of  cubic 
feet  of  water  displaced  below  a  given 
line  of  immersion,  we  assume  that  the 
draught  is  divided  into  longitudinal 
sections,  parallel  to  the  line  of  immer- 
sion, usually  called  water  lines.  To 
determine  the  amount  of  displacement 
is  to  compute  the  area  of  each  of  those 
planes  or  water-lines  from  the  half- 
breadth  plan,  (which  shows  the  shape 
of  the  vessel  longitudinally,)  and  the 
cubical  contents  of  the  spaces  be- 
tween those  lines.  In  Europe,  the 
line  of  flotation,  or  the  inscribed 
line  at  the  surface  of  the  water, 
is  called  the  first  water-line,  or  load- 
line,  and  as  they  descend  the  numbers 
increase.  In  the  United  States  the 
lowest  water-line  is  denominated  the 
first,  and  the  numbers  increase  as  we 
ascend.  The  greatest  immersed  line 
of  flotation  is  universally  called  the 
load-line ;  and  the  usual  mode  of  cal- 
culation commences  with  the  load-line, 
which  is  divided  into  equal  spaces,  by 
lines  running  at  right  angles  with  the 
middle  line  in  the  half-breadth  plan. 
Those  lines  represent  frames,  and  are 
numbered  in  the  after-body,  (or  from 
the  largest  frame  toward  the  stern,) 
and  lettered  in  the  fore-body,  (or  from 
the    largest    frame   toward   the   bow,) 


MARINE    AND    NAVAL    ARCHITECTURE 


35 


commencing  at  the  extreme  breadth  or 
greatest  transverse  section.  In  thus 
dividing  the  ship  longitudinally  into  sec- 
tions, it  is  in  all  cases  proper  to  place 
this  frame,  representing  the  greatest 
breath,  and  having  the  greatest  area, 
in  such  place  that  it  may  prove  to  be 
what  it  represents.  It  is  usually  de- 
nominated dead  flat,  from  its  having 
less  rise  on  the  floor  than  the  rest  of 
the  frames  in  the  ship.  It  is  usually 
marked  ®.  The  location  of  this 
frame  should  be  known  before  the 
shape  of  the  half-breadth  plan  is  deter- 
mined. It  will  be  seen,  that  to  make 
the  spaces  equal  between  the  frames, 
the  division  or  setting  off  must  proceed 
from  <g>  frame  in  each  body  ;  and  that 
if  the  frames  are  to  be  2^  feet  apart, 
every  fourth  frame  will  be  10  feet 
apart.  It  will  be  only  necessary  for  our 
present  purpose  to  consider  the  fourth 
frames,  until  we  approach  the  extremi- 
ties, when  Ave  may  include  every  second 
frame,  and  at  the  extremes,  sometimes, 
every  frame.  See  the  Displacement 
Tables  of  Plate  2. 

The  stability  of  vessels  is  an  impor- 
tant branch  of  hydrostatics,  and  is 
among  the  first  considerations  that 
should  engage  the  attention  of  the 
builder.  There  are  two  kinds  of  sta- 
bility, natural  and  artificial,  speaking  in 
general  terms. 

It  has  been  already  shown,  that   the 


bulk  of  water  displaced  by  the  vessel 
must  have  a  central  point  or  axis  upon 
which  it  would  equilibriate  if  congealed. 
And  this  has  been  denominated  the 
centre  of  displacement,  or  the  centre  of 
gravity  of  displacement.  It  does  not, 
however,  follow  as  a  consequence,  that 
this  point  is  to  be  found  only  in  the 
centre  of  the  cavity,  either  longitudi- 
nally or  vertically  ;  but  if  the  two  sides 
of  the  vessel  are  alike,  it  will  always 
be  found  in  the  centre,  transversely, 
when  the  vessel  is  upright.  Neither 
does  it  follow,  that  this  assumed  axis  is 
immoveable,  or  always  in  the  same 
place  ;  but  whenever  the  vessel  is  ca- 
reened, or  drawn  aside  from  an  upright 
position,  or  a  change  takes  place  in  the 
shape  of  the  line  of  flotation,  the  centre 
of  gravity  of  displacement  changes  its 
location,  unless  the  body  is  homoge- 
neous, or  of  such  shape  as  to  create  no 
change  in  the  form  of  the  cavity.  In 
such  case,  if  the  body  is  of  equal  den- 
sity the  centre  of  gravity  becomes  the 
axis.  A  second  axiom  may  be  deduced 
from  this  law  of  equilibriated  gravity 
in  bulks,  in  the  seeming  paradox,  that 
the  centre  of  gravity  is  not  the  centre 
of  motion.  In  all  bodies  floating  on 
fluids,  and  only  partially  immersed,  the 
line  or  point  of  support  has  a  separate 
and  distinct  location,  unless  as  before 
stated.  The  body  is  homogeneous  in 
shape,  and  of  equal   density;  in  such 


3G 


MARINE   AND    NAVAL    ARCHITECTURE. 


case  it  has  no  stability.     It  will  appear 
quite  manifest,  upon    a    moment's  re- 
flection,   apart    from    the    conclusions 
drawn  from  mathematical  investigation, 
that  a  body  having  its  centre  of  gravity 
depressed  below  its  vertical  centre,  and 
suspended  by  a  point  above  the  vertical 
centre,  such  body  would  be  subject  to 
less  oscillatory  motion,  than  if  suspend- 
ed at  the  centre  of  gravity.     He.nce  it 
follows,  that  to  depress  the  centre  of 
gravity,  and   elevate   the  point  of  sup- 
port, is   to   increase   the   stability  of  a 
body  thus  suspended.     It  is  a  conced- 
ed point,  a  truth  with  which  all  are  fa- 
miliar, that  all  bodies  are  supported  by 
the  centre  of  gravity  ;  and  that  it  re- 
quires a  force  more  than  equal  to  the 
weight  of  the  entire  bulk,  to  lift  that 
body  when  applied  to  this  centre  ;   and 
that  the  body  thus   suspended  has  no 
stability,  but  revolves  around  this  cen- 
tre.    Not  so,  however,  with  a  body,  or 
vessel,  floating  on  a  fluid  and  sustain- 
ing the  pressure  of  two  elements — the 
centre  of  gravity  loses  its  influence  as 
a  point   of  support,   because  the   fluid 
beneath  is   non-elastic,  and  of  greater 
density  than  the  fluid  above.      Thus  it 
is  plain,  that  the  forces  of  the  fluid  up- 
ward  must   exceed   the    forces  of  the 
fluid  downward,  or  there  is  no  stability. 
The  effort  of  the  waters  power  to  sus- 
tain  a    vessel  in    an    upright  position, 
passes  through  the  centre  of   cavity,  or 


gravity  of  displacement,  and  the  direc- 
tion of  its  effort  is  perpendicular  to  the 
surface  of  the   fluid.      Therefore,  if  a 
vessel  is  at  rest,  and  in  smooth  water, 
her  centre  of  gravity  is   in  the   mean 
direction    of    the   effort    of  the  water 
which  supports  her.      When  a  vessel  is 
inclined,  or  heels,   she   should   have  a 
tendency  in  herself,  without  ballast,  to 
regain  her  upright  position  :  that  is  to 
say,  her  centre  of  gravity  ought  to  be 
so    sustained,   that    the    effort    of  the 
vessel's  weight  should  concur  with  the 
effort  of  the  water  to  right  her.      This 
concurrence  of  efforts  is  what  may  be 
properly  termed  stability,  and  its  pro- 
portions may  be  measured  ;  and  as  the 
inches  upon  a  rule  show  the  proportions 
of  a  foot,  so  the  altitude  of  the  point  I 
shall  denominate  the    centre  of  effort, 
may  be  measured,  and  the   amount  of 
stability  determined.     It  should  be  re- 
membered, that  the  centre  of  effort  is 
that  point  in  the  vertical  section  of  the 
vessel's  length,  at  the  middle  line,  under 
which  the  centre  of  gravity  of  the  ves- 
sel ought  always  to  be,  in  order  to  pre- 
vent   the    vessel    from    falling  on   her 
beam  ends,  or  turning  bottom  up. 

The  measure  of  stability,  or  centre 
of  effort,  is  also  a  moveable  point,  and 
changes  its  position  at  every  change  in 
the  line  of  flotation,  the  stability  of  the 
vessel  being  determined  by  the  altitude 
of  the  centre  of  effort,  or  its  distance 


MARTNE  AND    NAVAL    ARCHITECTURE, 


37 


from    the    centre    of    gravity,    which 
remains   unaltered    while   the    vessel's 
weight   is   the   same,  and  is   homoge- 
neous.    It  will  be  necessary,  in  order 
that  the  reader  may  be  made  familiar 
with    the    locality   of  those   moveable 
points,  to   make  a   proper   distinction 
between  the  two  centres  of  gravity  ; 
that  of  the  entire  vessel  we  shall  de- 
nominate the  centre  of  absolute  gravity, 
while  the  centre  of  gravity  of  displace- 
ment we  may  know  as  the  centre  of 
cavity,  or  under  its  former  appellation. 
It  will  be  perceived,  that  as  the  vessel 
is  immersed  by  the  reception  of  cargo 
to  a  more  elevated  line  of  flotation,  the 
centre  of  the  absolute  gravity  descends, 
not  because  the  body  is  heavier,  but 
because  it  is  not  homogeneous,  or  be- 
cause the  lower  part   of  the  vessel  is 
heavier  than  the   topsides  by  the  addi- 
tional weight  of  cargo,  the  centre  of 
cavity  has  taken  a  higher  position  con- 
sequent  upon  the  increased  displace- 
ment, and   as    every   addition    to    the 
displacement   must   take   place  at  the 
surface  of  the  fluid  and  increase   the 
altitude  of  the  line  of  flotation,  so  the 
results  of  such  increase  will  be  seen  in 
the  increased  altitude  of  the  centre  of 
this  displaced  bulk  of  fluid  or  the  centre 
of  cavity.    The  centre  of  effort  may  be 
thus  defined :    It   is  the  centre   of  di- 
rection  of  all  the  forces  that   support 
the  vessel ;    this  leads  us  to  a  point, 


the  consideration  of  which  we  will  defer 
to  a  subsequent  chapter.     The  equili- 
brium of  fluids  should  teach   us  this 
truth,  that  the  pressure  of  the  fluid,  or 
the   direction   of  the  resistance,  is   at 
right   angles  with   the  surface  of  the 
body,   or  the    exterior  surface   of  the 
cavity  made   by  the   vessel ;   hence,  it 
follows,  that  to  find  the  centre  of  effort 
of  a  floating  body,  is  to  find  the  centre 
of  that  force  enabling  a  ship   to  pre- 
serve an  equilibrium   perpendicular  to 
the  surface  of  the   fluid  by  which  she 
is    sustained.       This    point    is    always 
found   to  be   in   the   centre   of  cavity 
when  the  vessel  is  in  an  upright  posi- 
tion,  and  it  is  equally  apparent,  that 
when  a  vessel  is  at  rest  in  smooth  wa- 
ter, the  centre  of  gravity  is  in  the  mean 
direction  of  the  effort  of  the  fluid  that 
sustains  her.     In  other  words,  the  cen- 
tre of  effort    is  the  centre   of  the   for- 
eign power  that  deprives  the  centre  of 
gravity   of  much    of  its    influence   in 
floating  bodies.     It  will  be  readily  seen, 
that,  were  lines  drawn  at  right  angles 
from  every  part  of  the  exterior  surface 
of  the  vessel   inward,  to  the  longitu- 
dinal    and     vertical    plane     extending 
through  the  vessel,  or  the  line  known 
as  the  middle  line,  those  lines  running 
from  the  section  near  the   keel,  would 
point    higher  than  those  coming  from 
the  bilge,  and   those   coming  from  the 
bilge  would  extend  higher  than  others 


38 


MARINE    AND    NAVAL    ARCHITECTURE. 


near  the  surface.  Thus,  the  sum  total 
of  the  effort  of  all  those  lines  of  direc- 
tion, either  adjacent  to  the  keel  and 
pointing  upwards,  or  those  from  the 
bilge  and  pointing  diagonally,  or  those 
near  the  surface  and  pointing  horizon- 
tally, the  sum  total  of  those  efforts  is 
the  point  I  have  denominated  the  cen- 
tre of  effort.  Hence,  it  follows,  that 
the  altitude  of  the  centre  of  effort  upon 
which  so  much  depends,  is  consequent 
upon  the  dimensions  more  than  artifi- 
cial moans,  and  as  we  increase  the 
breadth  of  vessels,  we  elevate  it ;  so,  in 
the  same  ratio  we  depress  it  when  we 
diminish  the  breadth  or  increase  the 
depth.  A  case  in  point  may  serve  as 
an  exposition  to  illustrate  the  princi- 
ples upon  which  the  stability  of  all 
vessels  depend,  perhaps  better  than  any 
the  author  may  be  able  to  adduce. — 
Assuming,  that  a  ship  built  for  com- 
mercial purposes  is  found  to  possess 
a  precarious  amount  of  stability,  and 
as  a  consequence,  must  carry  ballast 
in  her  hold  to  create;  an  artificial  sta- 
bility and  secure  an  upright  position  ; 
we  will  now  determine  the  location  of 
the  centre  of  the  absolute  gravity,  the 
centre  of  cavity,  and  the  centre  of 
effort  ;  the  two  latter,  in  this  instance, 
will  remain  stationary,  while  the  centre 
of  absolute  gravity  will  be  the  moveable 
point,  when  a  change  in  tin;  location 
of  the  ballast  takes  place.      Having  the 


precise  location  of  all  the  moveable 
centres,  we  will  now  proceed  cau- 
tiously to  remove  the  ballast  on  deck. 
We  shall  perceive  that  the  stability  of 
the  vessel  diminishes  very  last,  and  be- 
fore the  ballast  is  half  removed  from 
the  hold,  it  will  be  necessary  to  use 
precautionary  measures  to  maintain 
an  upright  position,  or  the  position 
the  vessel  maintained  when  we  com- 
menced. Under  such  circumstances, 
is  it  not  plain  that  the  centre  of  cavity 
has  remained  in  the  same  place  ?  The 
vessel  displaces  no  more  water  than 
before,  the  ship  and  ballast  weigh 
the  same,  whether  it  is  all  in  the  hold, 
or  part  in  the  hold  ami  part  on  deck  ; 
and  as  it  is  the  centre  of  the  bulk  of 
water,  and  the  bulk  is  the  same,  so  in 
like  manner  the  centre  must  be  at  the 
same  point.  It  is  equally  as  palpable 
that  the  centre  of  effort  has  remained 
in  the  same  place,  as  that  point  is  del- 
egated to  represent  all  the  forces  of 
the  lines  of  direction  of  the  immersed 
part  of  the  hull ;  and  if  the  immersed 
surface  remains  unchanged,  both  in 
form  and  bulk,  the  nature  and  extent 
of  that  delegation  are  the  same.  We 
will  now  inquire  into  the  nature  and 
extent  of  the  change  that  has  pro- 
duced such  wondrous  results.  We 
have  already  discovered  that  the  cen- 
tre of  gravity  is  an  immoveable  point, 
while  the  weight   of  the   body  remains 


MARINE    AND    NAVAL    ARCHITECTURE. 


39 


unchanged,  and  is  homogeneous ;  but, 
although  the  ship  and  ballast  weigh 
precisely  the  same,  whether  in  the  hold 
or  on  deck,  yet  the  body  or  the  ship, 
in  this  instance,  is  not  homogeneous ; 
when  the  ballast  was  in  the  hold,  the 
bottom  was  the  most  dense  ;  and  now, 
as  consequent  upon  the  change,  the 
topsides  are  more,  and  the  bottom  is  less 
dense  ;  hence  the  reason  of  the  instabil- 
ity when  the  ballast  is  removed,  the  cen- 
tre of  gravity  has  changed  its  position, 
its  altitude  has  been  increased.  This 
leads  us  to  another  proposition :  nei- 
ther the  centre  of  effort,  the  centre  of 
cavity,  or  the  centre  of  gravity  is  the 
oscillating  point  or  the  fulcrum  upon 
which  this  stupendous  fabric  moves. 
When  the  centre  of  gravity  is  located 
below  the  surface  of  the  fluid,  the  os- 
cillating point  is  found  at  the  surface ; 
but  when  the  centre  of  gravity  is  at 
the  same,  or  a  greater  altitude,  itself 
becomes  the  oscillating  point,  as  all 
bodies  above  the  surface  of  the  water 
oscillate  upon  that  point.  The  several 
centres  may  be  represented  by  the  or- 
dinary store-keepers'  scale-beam  ;  upon 
the  nail  or  point  of  suspension  depends 
the  weight  of  the  scales,  weights,  and 
articles  weighed  ;  this  point  is  at  a 
greater  altitude  than  the  fulcrum  upon 
which  the  beam  oscillates,  while  the 
scales,  in  their  distended  capacity,  are 
found  still  lower.     So  with  those  points 


of  measurement  of  stability  ;  the  centre 
of  effort  to  which  is  delegated  the 
power  of  contending  with  a  combina- 
tion of  forces  emanating  from  two  ele- 
ments, is  the  highest  power ;  the  ful- 
crum, or  the  oscillating  point,  or  centre 
of  motion,  is  located  at  the  surface,  as 
the  fulcrum  is  at  the  surface  of  the 
beam,  while  the  centre  of  cavity  and 
the  centre  of  gravity  take  their  places, 
like  the  scales  at  less  elevated  positions. 
From  what  has  been  shown,  this  truth 
is  deducible,  that  by  increasing  the 
breadth  of  a  vessel,  we  increase  the 
stability,  and  elevate  the  centre  of 
effort,  or  increase  the  distance  be- 
tween the  centre  of  effort  and  the  cen- 
tre of  absolute  gravity.  But,  another 
fact  worthy  of  our  consideration  claims 
our  attention.  Every  vessel  has  a 
natural  position,  or  a  position  pecu- 
liar to  the  shape  of  the  vessel  when 
launched.  For  example,  if  the  great- 
est transverse  section  is  forward  of  the 
longitudinal  centre,  and  the  usual  pro- 
portional expansion  of  the  lines  for- 
ward, and  contraction  aft,  take  place 
in  the  formation  of  the  vessel,  it 
causes  her  to  set  by  the  stern  ;  this  is  a 
fact  with  which  all  are  familiar,  but  it 
must  not  be  supposed  that  the  launch- 
in"  line  of  flotation  is  the  natural  line 
of  immersion.  In  order  to  obtain  this, 
the  model  should  be  separated  at  the 
line    of    flotation,    at    which    the    na- 


40 


MARINE    AND    NAVAL    ARCHITECTURE 


tural  position  is  required.  Another 
illustration  may  serve  better :  A  log 
of  timber  is  said  to  be  propelled  with  a 
given  speed  with  less  force  the  butt 
end  foremost  than  the  small  end ;  the 
reason  of  this  is,  that  nearly  all  of  the 
resistance  to  be  overcome,  is  found  at 
the  ends,  the  pressure  of  the  water 
being  at  right  angles  with  the  bottom 
and  sides  of  the  log  ;  in  connection 
with  the  fact,  that  the  log  draws  the 
most  water  at  the  butt,  which  materi- 
ally diminishes  the  friction  when  the 
log  is  in  motion  ;  whereas,  if  the  small 
end  were  foremost,  the  friction  would 
be  augmented  by  this  right-angled  pres- 
sure. Philosophers  have,  by  this  over- 
sight, done  the  science  of  ship-building 
no  material  service.  Builders  have 
been  led  to  suppose  that  a  full  bow, 
and  a  thin  after  end,  with  large  but- 
tocks to  keep  the  vessel  from  going 
down  aft  altogether,  was  the  proper 
shape.  I  shall  endeavour  to  show,  in 
the  proper  department  of  this  work, 
that  this  error  has  proved  fatal  to  the 
commercial  world.  In  civil  architect- 
ure, an  extravagance  or  a  blunder, 
may  be  an  eye-sore  to  men  of  taste, 
and  render  the  projector  of  the  design 
ridiculous;  but  in  marine  and  naval 
architecture,  it  too  often  proves  fatal 
to  human  life. 

We  may  be  able  to  give  another  ex- 
position of  the   laws  of  stability,  by  a 


practical  illustration  from  a  pine  log. 
It  is  well  known,  that  a  log  straight 
and  squared  both  ways  to  an  equal 
size,  whose  specific  gravity  does  not 
exceed  three-quarters  of  the  specific 
gravity  of  water,  will  not  float  with 
either  of  its  planes  parallel  to  the  sur- 
face of  the  water  ;  assuming  that  its 
specific  gravity  is  exactly  three-quar- 
ters that  of  the  water  in  which  it 
floats,  with  which,  under  some  cir- 
cumstances, yellow  pine  is  found  to 
comply  with  the  already  expressed 
terms  of  proportion.  From  what  has 
been  shown,  a  bulk  of  water,  three- 
quarters  of  the  entire  bulk  of  the  log51 
will  weigh  as  much  as  the  entire  log; 
hence,  it  follows,  that  only  three-quar- 
ters of  the  log  will  be  immersed,  or 
that  a  line  of  flotation,  three-quarters 
of  the  distance  up  from  the  base  on 
the  two  perpendicular  planes  or  sides, 
would  satisfy  the  demands  of  weight. 
The  log  is  supposed  to  be  homogeneous, 
hence,  the  centre  of  the  absolute  gra- 
vity is  found  in  the  centre  of  the  log 
longitudinally,  and  the  centre  of  motion 
is  at  the  surface,  the  centre  of  effort  is 
found  to  be  at  the  centre  of  gravity; 
hence,  it  is  plain  there  is  no  stability 
while  the  log  remains  with  one  of  its 
planes  parallel  to  the  surface  of  the 
water,  and  will  not  rest  until  it  as- 
sumes a  position  that  will  separate  the 
centre  of  effort  from  the  centre  of  the 


MARINE    AND   NAVAL    ARCHITECTURE 


41 


absolute  gravity  at  the  farthest  possible 
distance  ;   and  if  this  separation  cannot 
be  made,  the  log  will  have  no  stability 
in  any  position  ;  hence,  the  reason  why 
a  log,  as  described,  will  assume  a  posi- 
tion, in  which  two  of  its  corners  form 
a  vertical  line,  and  the  other  two  being 
at  right  angles  with   the  first,  will,  as 
a  Consequence,  be  parallel  to  the  sur- 
face.    Thus  it  will   be-  seen  at  once, 
that    the    right-angled    pressure    from 
the   exterior   surface   inward,   is  of  a 
more  elevated  character,  and  raises  the 
centre  of  effort   above  the  centre  of 
absolute    gravity,   in    the    same    ratio 
that  the   proportion   of  breadth  is  in- 
creased over  the  draft  of  water.    Assu- 
ming the  log  to   have  been   12  inches 
square,  the  draft  of  water  was  9  inches, 
while   the   breadth  was  12  ;   but  when 
the  log  was  canted,  the  breadth  was  17 
inches,  while  the  draft  of  water  was  but 
11.    In  the  former  case,  the  centre  of 
cavity  was  one  inch  and  a  half  below 
the  centre  of  absolute  gravity,  while  in 
the  latter  it  was  but  one  inch ;   thus  it 
is  plain  that  the  stability  of  the  log  did 
not  depend  upon  the  depressed  location 
of  the  centre  of  cavity;  had  this  been 
the  case,  the  stability  would  have  been 
greatest  when  the  surface  of  the  log  was 
parallel  to  the  horizon,  as  it  was  then  at 
the  lowest  possible  point.    Is  it  not  plain 
that  the  direction  of  the  exterior  pres- 
sure is  upward  from  the  lower  edge  to 


the  extreme  corners  ?  Hence  it  follows, 
that  the  centre  of  effort  has  taken  a 
more  elevated  position,  and  as  in  this 
position   the  centre   of  effort    has  its 
highest  possible   location,   so  also   the 
log,  in  this  position,  has  its  greatest  sta- 
bility.    From  this  simple  illustration, 
we  may  deduce  this  truth,  that  vessels 
having   no   more   breadth  than  depth, 
have  no  stability ;  a  fact  too  well  de- 
monstrated by  vessels  that  have  been 
built  in  the  Eastern  states.     The  prin- 
cipal dimensions  of  vessels  have  much 
to  do  with  their  performances  beyond 
their  stability ;   a  small  addition  to  the 
topsides,  in   a  manner  that    does  not 
affect   their  depth  at  the  usual  meas- 
uring point,  may   not  only  greatly  di- 
minish their  stability,  but   affect     and 
counteract    the    very  object   for  which 
such  addition    was  made.      The   ship- 
owner does  not  seem   to  realize,  that 
for  the  additional  50  tons  of  weight  he 
has  added  to  the  weight  of  the  ship, 
in  what  is  usually  termed  top-hamper, 
or  in  houses,  poop-deck,  high  bulwarks, 
&c,  that  he  is  compelled  to  carry  100 
tons  of  ballast  more  than  without  it  ; 
thus,  one  hundred  and  fifty  tons  of  dis- 
placement are  lost,  or  worse  than  lost, 
being  actually  an   injury  to  the   per- 
forming  qualities   of  the   ship.      The 
notion  of  having  a  large   topside  on  a 
small  bottom,    is  without  a  basis  in  the 
principles  of  sound  philosophy  in  ship- 


42 


MARINE    AND    NAVAL    ARCHITECTURE. 


building,  its  deleterious  effects  will  be 
shown  in  connection  with  the  baneful 
effects  of  the  tonnage  laws  as  a  first 
cause  of  disproportions.  It  should  be 
remembered,  that  about  one-third  of 
the  length  of  most  vessels  has  no  sta- 
bility,  and  as  a  consequence,  the  coun- 
teracting leverage  must  be  supported 
by  the  bulkier  parts  of  the  vessel ; 
hence,  it  follows,  that  to  increase  the 
length,  (while  at  the  same  time  we 
possess  a  due  proportion  of  breadth,) 
is  to  increase  the  stability  of  a  vessel 
— another  demonstrable  truth  in  rela- 
tion to  the  stability  of  vessels.  It  is 
well  known  that  ships  have  been  built 
with  their  greatest  transverse  section 
so  formed,  that  its  extreme  breadth 
was  depressed  below  the  launching  line 
of  flotation,  while  the  depth  was  in- 
creased beyond  what  it  would  have 
been  in  an  ordinary  formed  vessel,  un- 
der the  false  notion,  that  if  the  breadth 
were  depressed,  the  vessel  would  be 
rendered  more  stable  than  otherwise. 
This,  to  some  extent,  is  true  ;  while  the 
vessel  is  without  cargo,  she  covers  a 
larger  surface  than  she  would  other- 
wise, and  as  a  consequence,  the  centre 
of  effort  is  higher,  and  the  centre  of 
the  absolute  gravity  lower,  by  such  a 
distribution  of  breadth,  and  such  ves- 
sels are  often  found  to  maintain  an 
upright  position  without  ballast,  with 
their  spars  and  rigging  adjusted ;  but 


let  such  ship  receive  her  cargo,  and 
perform  her  intended  voyage,  and  the 
story  is  soon  told.  She  is  found  to  be 
one  of  the  most  uneasy  vessels  that 
navigate  the  ocean.  The  reason  will 
appear  obvious  to  the  thinking  man, 
that  it  is  because  there  is  an  undue 
proportion  of  buoyancy  near  the  base, 
and  an  insufficiency  at  the  1<khI-1pu< 
of  flotation  ;  the  consequences  art 
plain  to  be  seen  :  this  expanded  buoy- 
ancy near  the  base  receives  nearly  all 
the  upward  pressure,  and,  consequent- 
ly, has  a  tendency  to  trip  the  vessel, 
while  at  the  surface  there  is  an  insuf- 
ficiency of  buoyancy  to  counteract  it, 
or  to  relieve  the  ship  from  those  sudden 
and  irregular  lurches  to  which  she  is 
constantly  exposed  ;  and  I  have  no  hesi- 
tancy in  saying,  that  the  testimony  of 
mariners  will  agree  with  the  deductions 
drawn.  It  should  be  remembered,  that 
although  the  points  delineated  are  in- 
visible and  moveable,  having  no  visible 
resting  place  in  the  hull  of  the  vessel ; 
yet  they  represent  forces  that  have  a 
tangible  locality  in  the  natural  world, 
and  are  an  index  to  the  destiny  of 
those  who  break  down  the  bulwarks 
of  creative  wisdom,  and  in  defiance  of 
nature's  laws,  rear  others  suited  to 
their  own  notions.  It  has  been  con- 
ceded by  men  of  science,  that  in  ar- 
ranging the  proportions  of  ships  suited 
to  navigate  the  ocean,  the  stability  is 


MARINE   AND    NAVAL    ARCHITECTURE, 


43 


the  first  consideration  ;  practical  know- 
ledge  has  added  weight  to  the  dogma, 
and  with  this  two-fold  evidence,  or  this 
collateral  testimony,    it  has  been  ren- 
dered  a  truism,   and   should  be  so  re- 
ceived.    For  general  reference,  it  may 
be  well  to  lay  down  certain  rules  with 
regard  to  the  augmentation  of  stability 
under    ordinary    circumstances.      Sta- 
bility, thus  circumstanced,  increases  as 
the  cubes  of  the  breadth,  as  by  adding 
one-quarter  to  the  breadth,  we  double 
the  stability,  and  as  a  consequence,  a 
capacity  to  carry  double  the  sail,  with 
but   (under   any    circumstances)    one- 
fourth    more     resistance.       In     every 
branch   of  mechanism,   wherein    pro- 
portions are  recognised  as  the  stand- 
ard of  utility,  it  is  found  necessary  to 
assume  one  portion  of  the  dimensions, 
in  order  to  proportion   the   remaining 
parts  to  the  first ;  this  course  is  quite 
as  essential  in  marine  and  naval,  as  in 
civil  architecture.     In  mercantile  sail- 
ing vessels  of  the  larger  class,  it  is  ne- 
cessary to  assume  the  depth  from  the 
base  line  to  what  is  sometimes  termed 
the  top  height,  or  the  lower  side  of  the 
plank    shear ;     two-thirds     of    which 
should  be  set  apart   for  the  immersed 
portion,  and  the  line  of  separation  may 
be  denominated    the  load-line,    or   the 
greatest    immersed     line   of   flotation. 
Having  thus  determined  the  depth  of 
the  vessel,  we  are  now  enabled  to  give 


a   proportionate     breadth    to    a    given 
depth ;  the  depth  of  the  vessel,  as  al- 
ready designated,  may  be   divided   into 
four  parts,  and  the  quotient  multiplied 
by  seven,  which  would  be  \  of  the  depth. 
Thus,  for  a  depth  of  22  feet  from  base 
to  plank  shear,  we  have  22  -h  4  =5.\  x 
7  =  384  feet,  this  would   be  a  propor- 
tionate breadth  for  ships  having  a  poop- 
deck  and  forecastle-deck,  but  without 
these,  |  would    be   quite    as  good   pro- 
portions;   in  smaller  vessels,  the  pro- 
portionate breadth  increases,  and  will 
be  delineated  in  a  part  of  the  work  set 
apart  for  that  class  of  vessels.      Steam- 
ers require  a  greater  proportion  of  beam 
than    any   other   description    of  large 
vessels — two  parts   of  breadth   for  one 
of  depth  have   been  found   to   be    the 
most    efficient    that     have     yet     been 
adopted.      It   must   be  quite   apparent 
to  the  thinking  man,  that  inasmuch  as 
the  centre   of  gravity  of  the   engine, 
boilers,  wheels,  &c.,  is  near  the  centre 
of  motion,   in  addition   to  which,  the 
vessel   having  less  stability  at  the  ex- 
tremities than  sailing  vessels,  demands 
a  greater  proportion  of  breadth  to  in- 
sure an  equal  amount  of  stability.      In 
reply  to  this  demand,  it  has  been  said, 
that  the  fuel  was  amply  sufficient  to 
restore  the  equilibrium  of  stability,  and 
thus  render  the  additional   breadth  un- 
necessary.     But    again,    it    should    be 
remembered,   that   although  n  steamer 


44 


MARINE    AND    NAVAL    ARCHITECTURE. 


might,  at  the  commencement  of  a  voy- 
age, be  found  to  possess  a  sufficiency 
of  stability,  having  the  proportionate 
breadth  of  sailing  vessels  ;  yet,  at  the 
end  of  the  voyage,  |he  would  possess 
much  less,  in  consequence  of  the  con- 
sumption of  her  ballast,  apart  from  the 
objectionable  features  of  artificial  sta- 
bility instead  of  natural,  and  the  con- 
sequent loss  of  speed,  to  which  ocean 
steamers  are  subject,  by  a  heavy  draft 
of  water.  Having  considered  the 
length  and  breadth  suitable  for  ships 
and  ocean  steamers,  we  will  now  pro- 
ceed to  determine  their  length  propor- 
tionate to  breadth ;  whether  the  object 
be  burthen  or  speed,  a  good  degree  of 
length  will  be  found  advantageous  ;  4\ 
times  the  breadth  for  the  length  on 
load-line,  or  5  times  the  breadth  for  the 
length  on  deck,  are  fair  proportions  ; 
and  should  the  smallest  ratio  of  beam  be 
selected,  the  length  may  be  increased 
to  advantage,  both  for  stability  and 
burthen.  The  author  is  aware,  that 
the  proportions  of  breadth  already 
given,  are  rarely  adopted ;  that  3  feet 
of  breadth  for  2  of  depth,  is  very  gene- 
rally regarded  as  good  proportions  for 
freighting  ships ;  he,  however,  challen- 
ges a  comparison  of  the  profits  accruing 
for  one  year,  of  two  ships  of  equal  dis- 
placement, one  having  the  proportions 
herein  laid  down,  and  the  other  having 
those  in  general  use,  even  though  the 


dark  and  forbidding  aspect  of  public 
opinion  and  popular  prejudice  stare 
him  in  the  face.  The  merchant  or 
builder  may  desire  a  knowledge  of  the 
weight  of  the  ship  he  owns  or  builds; 
and  as  the  process  of  calculating  the 
weight  of  all  parts  of  the  ship,  and 
every  piece  of  timber,  and  every  bolt, 
spike,  tree-nail,  &c,  is  tedious  and 
complex,  even  with  the  aid  of  the  hy- 
drostatic balance,  it  will  rarely  be  re- 
quisite to  have  more  than  an  approxi- 
mation to  the  truth.  True,  the  builder 
may  know  the  precise  weight  of  his 
ship  by  knoAving  the  displacement  be- 
low the  launching  line  of  flotation  ; 
but  when  the  ship  is  built  and  launched, 
it  is  too  late  to  make  alterations  how- 
ever desirable  ;  by  knowing  the  actual 
weight  of  the  ship  within  a  few  per 
cent,  before  she  is  built,  we  proceed 
with  more  confidence  in  the  prosecu- 
tion of  the  work  ;  by  knowing  the  dis- 
placement of  the  ship  below  the  load- 
line  of  flotation,  and  deducting  her 
weight  from  the  same,  we  have  the 
displacement  remaining  for  cargo.— 
Ordinary  sailing  ships,  for  freighting 
purposes,  from  5  to  800  tons,  weigh  -9 
of  their  load-line  displacement  ;  freight- 
ing ships  of  1000  tons  and  upward, 
weigh  one-half  of  their  load-line  dis- 
placement ;  ocean  steamers  weigh  from 
I  to  r,  of  their  displacement — this  ap- 
plies to  such  as  are  built  by  propor- 


MARINE    AND    NAVAL    ARCHITECTURE 


4-5 


tions  approximating  to  those  already 
given ;  when  these  dimensions  are  not 
adhered  to,  they  weigh  more.  Iron 
steamers  weigh  about  one-ninth  less 
than  those  built  of  timber.  For  an 
approximation  to  the  displacement  of 
sailing  ships,  multiply  the  three  princi- 
pal dimensions  together,  length,  breadth 
and  depth,  and  that  product  by  the 
ratio,  four-ninths,  or  one-half,  as  the 
case  may  require,  the  second  product 
by  the  weight  of  one  cubic  foot  of 
water,  the  last  product  divide  by  the 
number  of  pounds  in  a  ton,  the  result 
will  be  sufficiently  near  to  enable  us  to 
determine  something  in  reference  to 
the  dimensions  and  shape,  but  is  not  to 
be  relied  on  as  sufficiently  near  to  build 
by,  unless  we  are  indifferent  as  to  the 
amount  of  displacement.  The  ratio 
given  will  not  apply  to  ocean  steamers, 
without  immersing  them  too  deep,  as 
this  description  of  vessels  should  not  be 
immersed  more  than  five-eighths  of  their 
depth  of  hold,  and  if  they  have  more 
than  a  proportionate  depth,  nine-six- 
teenths of  their  depth  of  hold  should  be 
marked  as  their  load-line,  above  base- 
line, beyond  which,  they  should  not  go. 
In  approximating  the  displacement  of 
ocean  steamers,  the  ratio  may  be  seven- 
eighteenths.  There  is  another  rule 
that  is  sometimes  used  to  ascertain  the 
displacement  of  vessels:  multiply  the 
mean  of  the  lengths  of  the   keel  and 


between  perpendiculars,  by  the  area  of 
the  greatest  immersed  section,  or  ® 
frame  in  square  feet,  and  divide  this 
product  by  43  to  46  for  a  merchant 
ship — if  the  ship  be  fall,  take  the 
smaller  number.  This  rule  is  not  a 
reliable  one  for  ocean  steamers,  vary- 
ing from  48  to  62.  f>No  rule  can  be 
made  that  may  be  deemed  reliable  for 
all  descriptions  of  vessels  apart  from 
the  calculation  itself,  or  the  several 
modes  described  and  illustrated  by  the 
diagrams,  viz.,  comparative  weight  or 
comparative  bulk,  with  the  aid  of  the 
hydrostatic  balance. 

Mr.  Pook,  naval  constructor  at  Char- 
lestown,  Mass.,  has  discovered  an  inge- 
nious mode  of  deterrMning  the  capacity 
of  vessels  ;  and  its  approximation  to  the 
actual  displacement  of  government  and 
ordinary  freighting  ships,  renders  it  val- 
uably its  ready  application  to  such 
vessels  as  have  had  their  displacement 
calculated,  will  enable  the  reader  to 
test  its  accuracy.  Adapted,  as  it  is,  to 
almost  all  descriptions  of  freighting 
vessels;  very  sharp  vessels,  and  parti- 
cularly our  sharpest  ocean  steamers, 
are  exceptions  to  the  general  rule, 
having  a  smaller  displacement  than  the 
rule  would  give,  owing  to  their  having 
no  dead  rise,  and  an  easy  bilge.  The 
rule  is  as  follows:  From  90^  deduct 
the  angle  of  the  floor,  or  the  degrees 
of  dead  rise ;    multiply    by    ,0075    the 


46 


MARINE  AND  NAVAL  ARCHITECTURE 


quotient  is  the  decimal  for  capacity — 
multiply  the  length  by  the  breadth,  and 
that  product  by  the  depth,  from  the 
bottom  of  the  garboard  to  load-line, 
and  the  last  product  by  the  decimal  of 
capacity,  and  divide  by  35,  the  quotient 


is  the  capacity  in  tons.  Thus  assu- 
ming a  ship  to  be  160  feet  long,  35 
feet  wide,  and  from  the  bottom  of  the 
garboard  to  load-line  14  feet  deep,  with 
four  degrees  of  dead  rise,  as  in  Fig.  6. 
Thus  we  have — 


Decimal  Cubic  feet 

of  Capacity.      Length.      readth.  Depth.  Exponent.  per  ton. 

90°  — 4°=  86° X.  0075  =,645    160  X  35  =  5600  x  14  =  78400  x,  645  =  50568  -H  35  =  1444  capacity  in  tons. 


The  principal,  and  perhaps  the  only 
difficulty  in  applying  this  rule  as  a 
standard  of  measurement,  is  its  liability 
to  evasion,  (which  is  the  most  objec- 
tionable feature  in  the  present  law.) 
The  load-line  could  not  be  marked  a 
proportionate  distance  from  the  base- 
line or  from  the  plank-shear,  without 
exposing  the  law  Jo  the  same  amount 
of  infractions  the  present  one  is.  But, 
as  a  ready  rule  for  general  reference 
and  approximating  the  truth,  Mr. 
Pook's    rule    is    doubtless    without    a 


rival.  After  the  actual  displacement 
has  been  found,  a  very  convenient 
method  of  obtaining  the  capacity  will 
be  found  in  the  following :  Multiply 
the  length  between  perpendiculars  by 
the  breadth,  that  product  by  the  depth 
from  base  to  load-line,  this  last  pro- 
duct divided  into  the  whole  displace- 
ment, and  the  quotient  w  ill  furnish  the 
exponent  of  the  ratio  of  capacity,  and 
will  apply  equally  well  to  all  descrip- 
tions of  vessels. 


MARINE  AND  NAVAL  ARCHITECTURE 


47 


CHAPTER     II. 

An  Exposition  of  the  Tonnage  Laws — Their  Deleterious  Effects — Necessity  of  Change — Tonnage  Laws  of 

other  Nations — Laws  of  Resistance — Laws  of  Propulsion. 


Having  endeavored  to  show  that  re- 
liable proportions  cannot  be  furnished 
apart  from  mathematical  demonstra- 
tion, we  shall  now  proceed  to  show  the 
deleterious  effects  of  the  Tonnage  Laws 
upon  the  commerce  of  the  United 
States.  It  has  been  a  matter  of  no 
little  surprise  to  scientific  men  in  the 
old  world,  that  a  country  like  ours 
should  continue  in  force  laws  so  de- 
trimental to  her  commercial  interests 
as  the  existing  tonnage  laws  have 
proved  to  be  ;  nor  is  the  surprise  con- 
fined to  the  old  world:  our  ship-build- 
ers have  long  witnessed  its  baneful 
effects,  and  nothing  but  an  indomita- 
ble energy  has  saved  us  from  defeat  in 
our  race  with  England  for  the  ascen- 
dency in  building  ships.  The  hoary, 
the  venerated  prejudices  of  their  fathers 
has  too  much  influence  to  allow  the 
ship-owner  to  think  for  himself,  in  con- 
nection with  a  growing  jealousy,  lest 
the  builder  should  foster  his  own  in- 
terest, while  marking  out  a  course  for 
the  measurement  of  ships,  more  conge- 
nial to  the  spirit  of  the  age,  and,  as  a 
consequence,  avarice  has  been  permit- 


ted to  riot  without  control.  But  I 
pause  to  give  place  to  the  introduction 
of  a  new  era  in  the  commercial  world. 
The  change  that  has  taken  place  in 
the  British  Navigation  Laws,  and  the 
consequent  reciprocal  change  in  those 
of  the  United  States,  has  awakened  in 
the  two  greatest  commercial  nations 
on  the  globe,  a  rivalry,  that  in  less 
than  five  years  will  revolutionise  the 
commercial  world.  Had  the  United 
States  a  code  of  tonnage  laws  worthy 
of  the  name,  she  would  have  nothing 
to  fear ;  but  with  her  present  laws, 
actually  inviting  fraud,  she  has  much 
to  dread ;  the  terms  are  now  unequal, 
the  odds  are  against  us,  and  the  ship- 
owner will  soon  find  that  it  is  not 
enough  to  have  equally  as  good  a  sail- 
ing ship,  and  one  that  will  carry  as 
much  per  every  ton  of  displacement 
as  his  rival,  but  that  he  must  carry 
more,  and  sail  faster,  if  he  would  suc- 
cessfully compete  in  this  commercial 
race;  this  a  ship  with  large topsides  on 
a  small  bottom  cannot  do.  We  should 
remember  that  English  ships  are  now 
built   under  the   fostering  influence  of 


48 


MARTNE   AND    NAVAL    ARCHITECTURE. 


the  best  code  of  laws  on  the  globe, 
while  we  are  building  under  those 
among  the  most  heterogeneous  ;  and 
although  the  great  bulk  of  English 
ships  may  have  been  built  prior  to  the 
alteration  of  her  tonnage  laws,  yet 
these  are  not  the  ships  that  are  to  be 
our  rivals.  As  the  author  has  already 
stated  in  substance,  the  American  has 
nothing  to  fear  when  his  energies  can 
be  concentrated  on  a  single  point  with 
the  world  combined  in  the  race  to 
wealth  or  fame.  It  is  between  the 
conflicting  interests  of  successfully 
competing  with  his  rival,  and  the 
amount  of  dollars  supposed  to  be  saved 
in  tonnage  dues  by  disproportionate 
ships ;  and  if  we  are  lost  in  this  rival 
race,  it  will  be  found  that  we  have 
foundered  in  the  straits  of  avarice. 

It  is  mortifying  to  witness  in  the 
shipwright  the  mere  mechanic.  It  is, 
indeed,  humiliating,  to  see  the  most 
prominent  intellectual  art  in  the  cata- 
logue, reduced  to  a  mere  drudgery. — 
In  these  days  of  competition  and  hard 
utilitarianism,  it  is  not  only  a  pure  re- 
lief to  the  mind,  but  a  source  of  high 
enjoyment  to  the  man  who  has  kept 
an  idea  constantly  before  him,  and  has 
followed  it  with  a  fearless  and  faithful 
heart.  It  is  he  alone  who  can  look 
through  the  perspective  labyrinths  of 
futurity,  to  an  era  when  nothing  will 
be  acknowledged  beautiful  that  is  not 


true  ;  when  ships  will  not  only  be  built 
with  reference  to  utility  alone,  but 
measured  by  the  same  standard. 

It  cannot  be  denied,  that  our  ton- 
nage laws,  as  they  now  exist,  have 
done  more  to  clog  the  wheels  of  im- 
provement  in  marine  architecture,  than 
everything  beside  ;  whether  we  regard 
them  as  the  parent  of  legalized  fraud, 
or  as  the  fruitful  source  of  premature 
graves,  their  deleterious  effects  are 
alike  obvious  to  the  thinking  portion 
of  the  commercial  world.  While  the 
present  practice  prevails,  of  accounting 
the  one-half,  or  any  proportion  of  a 
ship's  breadth  for  the  depth,  it  must  be 
quite  apparent  that  ships  will  be  dis- 
proportioned,  and,  consequently,  unfit 
for  navigating  the  ocean  ;  by  a  dimin- 
ished breadth,  and  an  increased  depth, 
the  ship-owner  registers  his  ship  at 
much  less  than  her  actual  tonnage, 
and,  as  a  consequence,  that  wholesome 
competition  which  in  every  other  enter- 
prise is  the  muscle  of  improvement,  is 
rendered  weak  and  inefficient.  Me- 
chanics finding  their  boldest  thoughts 
and  best  exertions  fettered  by  the  on- 
erous burdens  entailed  upon  commerce, 
have  partially  lost  the  laudable  ambi- 
tion to  excel,  they  once  possessed,  and, 
like  ship-owners,  seem  to  have  forgot- 
ten, in  their  haste  for  the  dollar,  that 
our  ships  perforin  little  better,  or  make 
a  voyage   in   no  less  time   across  the 


MARINE    AND   NAVAL    ARCHITECTURE. 


49 


ocean  than  they  did  forty  years  ago. 
Startling  as  this  announcement  may 
appear,  it  is  nevertheless  true,  that 
voyages  of  thirteen  and  fourteen  days, 
from  this  city  to  Liverpool,  by  sailing 
ships,  were  as  frequent  forty  years  ago 
as  they  now  are.  It  will  not  be  de- 
nied, that  there  arc  ships  owned  in 
this  city,  that  under  the  same  circum- 
stances in  which  the  best  voyages 
have  been  made,  would,  without  doubt, 
perform  the  voyage  within  eleven 
days  ;  but  those  ships  are  engaged  in 
a  trade  over  which  the  tonnage  laws 
have  no  warping  influence  ;  I  allude 
to  the  trade  with  China.  The  profits 
accruing  from  our  commercial  inter- 
course with  that  remote  nation,  is 
found  to  consist  in  the  quick  returns, 
rather  than  the  bulk  of  cargo  ;  hence, 
the  reason  why  no  notice  is  taken  of 
the  inducement  to  evade  the  provisions 
of  the  present  law,  and  the  results  are, 
that  Canton  has  already  been  meas- 
ured as  distant  but  seventy-five  days 
from  New- York ;  and  the  day  is  not 
far  distant,  when  the  time  will  be  re- 
duced to  sixty.  There  is  one  feature 
in  political  science  that  teaches  us  that 
cheerful  submission  to  law  is  only  ren- 
dered when  based  on  the  principles  of 
equity  ;  when  its  wholesome  provisions 
bear  alike  on  all  its  subjects.  This 
great  principle,  the  glorious  bond  of 
union   in  this   republic,  will  be  found 


no  less  advantageous  to  our  commerce 
than  to  our  country.  England,  sensi- 
ble of  this,  abolished  her  heterogeneous 
code  in  1836,  since  which  time  her 
improvements  have  been  without  a  pa- 
rallel in  the  history  of  the  commercial 
world.  In  framing  a  law  that  will 
equalize  the  burdens,  and  make  com- 
petition a  fair  and  laudable  enterprise, 
making  the  ship  something  more  than 
a  mere  floating  warehouse,  and  at  the 
same  time  a  source  of  profit  to  her 
owners,  without  abridging  her  carry- 
ing properties  in  the  least,  but  rather 
augmenting  them  ;  and,  as  a  conse- 
quence, making  her  owners  greater 
returns  than  they  can  possibly  do  un- 
der the  existing  code,  and  giving  him 
an  equal  chance  for  the  rewards  of 
energy  and  enterprise  with  his  English 
competitor  under  the  reciprocal  navi- 
gation laws ;  it  needs  but  a  glance  at 
our  geographical  position  to  satisfy  the 
incredulous,  that  the  United  States  is 
destined  to  become  the  great  theatre 
for  commercial  improvements,  and  that 
it  only  remains  for  her  legislators  to 
enact  such  laws  as  will  cherish  a  spirit 
of  emulation  worthy  of  our  favoured 
locality,  and  of  the  age  in  which  we 
live,  to  place  her  far  in  advance  of 
other  nations  in  commercial  improve- 
ments. The  present  mode  of  deter- 
mining the  tonnage  of  ships  by  law,  is 
a  powerless  aid  to  science  and  emula- 


50 


MARINE    AND    NAVAL    ARCHITECTURE. 


tion,  and  no  sophistry  can  make  that 
right  which  common  sense  pronounces 
wrong.  It  only  remains  for  our  legis- 
lators to  be  true  to  the  instinctive  im- 
pulses that  have  prompted  the  exten- 
sion of  our  commercial  interest  to  the 
present  time,  and  this  monstrosity  in 
commercial  science  shall  be  found  only 
in  the  history  of  the  past.  Nature  has 
afforded  all  the  necessary  aid  ;  her  laws 
furnish  an  axiom  around  which  all 
may  rally,  and  feel  safe  in  the  assump- 
tion that  beauty  and  truth  are  commen- 
surate qualifications.  By  this  stand- 
ard of  principles,  we  are  willing  that 
the  science  of  marine  architecture 
should  be  weighed,  and  if  found  want- 
ing, let  the  fallacious  dogma  of  science 
in  this  seemingly  complicated  art,  be 
blown  to  the  winds.  Let  precedent  as- 
sert her  prerogative.  Let  ship-building 
stand  as  it  has  ever  stood  in  America, 
without  a  basis  of  principles.  Let  the 
continued  watch-word  through  the  un- 
measured vista  of  time  be  precedent. 
Let  the  mildew  of  hereditary  knowledge 
brood  over  the  genius  of  intellect  until 
the  march  of  science  shall  be  down- 
ward and  backward,  instead  of  upward 
and  onward.  It  is  one  of  the  wonders 
of  this  wonder-working  age,  to  see  the 
very  heavens  and  earth  bending  to 
American  genius,  and  every  element 
of  nature  made  subservient  to  man's 
comfort  and  convenience,  while  com- 


mercial science,  this  universal  alcahest, 
lies  like  a  statue  in  the  quarry.  The 
science  of  building  ships  is  kept  in 
dwarfish  imbecility  by  the  onerous  bur- 
dens entailed  by  legislation.  It  will  be 
rendered  at  once  apparent  to  the  dis- 
cerning mind,  that  to  equalize  the  ton- 
nage laws,  it  will  be  necessary  to  ob- 
tain the  actual  capacity,  which  may 
be  shown  in  cubic  feet,  tons,  chaldrons, 
or  bushels — this  mode  is  far  preferable 
to  that  of  regulating  the  tonnage  by 
displacement  or  weight — were  the  laws 
based  upon  displacement,  the  vessel 
carving  iron  would  perhaps  be  loaded 
when  but  half  full,  while  the  vessel 
carrying  cotton  would  scarce  be  loaded 
when  she  was  full ;  thus,  the  dues  of 
the  one-half  full  would  equal  those  of 
the  vessel  that  had  stowed  a  full  cargo. 
The  laws  respecting  the  measurement 
of  ships,  denominated  tonnage,  origi- 
nally implied  the  number  of  tons-weight 
a  vessel  might  safely  carry;  hence,  it 
will  be  readily  discovered,  that  it  has 
lost  its  original  signification,  and  is  not 
now  recognised  as  a  tangible  medium, 
but  as  a  fictitious  balance.  The  rule 
established  by  the  British  Parliament 
prior  to  1S36,  had  long  been  discovered 
to  be  founded  on  erroneous  principles, 
and  often  led  to  the  most  mischievous 
consequences.  Under  this  pernicious 
system,  vessels  came  to  be  built  narrow 
and  deep,  and  thus,  not  only  less  efli- 


MARINE    AND    NAVAL    ARCHITECTURE. 


51 


cient,  but  highly  dangerous ;  and  as 
early  as  1823,  a  committee  was  ap- 
pointed to  devise  measures  for  the  re- 
lief of  commerce  from  its  deleterious 
effects  ;  that  committee  recommended 
the  measurement  of  the  internal  capa- 
city, by  taking  the  breadth  and  depth 
at  each  quarter  of  the  length  ;  but  for 
some  reason,  no  step  was  taken,  and 
the  subject  slumbered  until  1832,  when 
another  committee  was  appointed  to 
consider  the  subject.  In  order  that 
the  committee  might  be  put  in  posses- 
sion of  all  the  available  information  pos- 
sible to  possess,  her  majesty's  govern- 
ment obtained  from  various  places  the 
modes  of  measuring  ship-tonnage,  and 
the  following  was  drawn  up  from  the 
documents  transmitted,  commencing 
with  England : — 

Divide  the  upper  deck,  between  the 
afterpart  of  the  stem  and  the  forepart 
of  the  stern  post,  into  six  equal  parts. 
At  the  foremost,  middle,  and  aftermost 
points  of  division,  measure  in  feet  and 
decimals,  the  depth  from  the  underside 
of  the  upper  deck,  to  the  ceiling  at  the 
limber  strake.  Divide  each  depth  into 
five  equal  parts,  and  measure  the  inside 
breadths  at  |th  and  |ths  (from  the 
upper  deck)  at  the  two  extreme  depths, 
and  at  Iths  and  ^ths  of  the  midship 
depth.  Measure  the  length,  as  above, 
at  half  the  midship  depth.  To  twice 
the  midship   depth,    add   the    extreme 


depths.  To  the  upper  and  lower 
breadths,  at  the  foremost  division,  add 
three  times  the  upper  and  lower 
breadths  at  the  midship  division,  and 
the  upper  and  twice  the  lower  breadth 
at  the  aftermost  division,  for  the  sum 
of  the  breadths.  Multiply  the  sum  of 
the  depths  by  the  sum  of  the  breadths, 
and  the  product  by  the  length,  and  di- 
vide this  product  by  3500,  the  result  is 
the  tonnage  for  register.  In  vessels 
with  a  poop,  or  a  break  in  the  upper 
deck,  measure  the  mean  length,  breadth 
and  height,  multiply  these  together, 
and  divide  by  92.4,  and  add  the  result 
to  the  former  quantity.  In  open  ves- 
sels, the  depth  is  measured  from  the 
upper  edge  of  the  upper  strake.  In 
steam  vessels,  the  tonnage  due  to  the 
contents  of  the  engine  room  (the 
depth  being  considered  at  the  midship 
depth,  and  the  breadth  at  jjths  of  this 
depth)  divided  by  92.4  is  to  be  de- 
ducted. The  relative  capacities  of 
ships  are  determined  very  nearly  by 
this  method.  In  France,  the  three 
measures  of  length,  breadth  and  depth, 
are  multiplied  together,  and  divided  by 
94,  for  the  tonnage.  In  single-decked 
vessels,  the  length  is  taken  from  the 
after  part  of  the  stem  on  deck  to  the 
stern  post ;  the  extreme  breadth  is 
taken  inside  from  the  ceiling,  and  the 
depth  from  the  ceiling  to  the  under 
side  of  the    deck;    in    vessels  of  two 


52 


MARINE    AND    NAVAL    ARCHITECTURE. 


decks,  at  Bordeaux,  the  length  of  the 
upper  deck,  and  that  of  the  keelson,  are 
meaned  for  the  length  ;  but  at  Brest, 
Marseilles,  and  Boulogne,  the  mean  of 
the  length  on  the  two  decks,  from  the 
stem  to  the  stern-post,  is  taken  as  the 
length  ;  the  depth  of  the  hold,  from  the 
ceiling  to  the  under  surface  of  the 
lower  deck,  is  added  to  that  of  the 
height  between  decks,  and  considered 
as  the  depth.  The  extreme  inside 
breadth  is  taken  as  in  single  vessels. — 
At  Bordeaux,  an  allowance  is  some- 
times made  for  the  rake  of  the  vessel. 
At  Boulogne,  in  measuring  steamboats, 
the  length  of  the  coal  and  engine 
chambers  is  deducted  from  the  length 
of  the  vessel,  and  her  breadth  is  taken 
at  the  fore  and  after  extremities  of  the 
same,  the  mean  of  which  is  considered 
as  the  breadth  ;  the  depth  is  taken  in- 
side of  the  pumps  from  the  lower  sur- 
face of  the  deck  between  the  timbers. 
At  Brest,  measures  are  frequently  ta- 
ken with  a  string,  although  contrary 
to  law,  and  an  error  of  seven  tons  in 
the  tonnage  of  a  cutter  has  been  the 
result.  In  Spain,  three  breadths  are 
measured  at  the  following  places  :  1st, 
at  the  mizzen-mast ;  2nd,  a  few  feet 
abaft  the  fore-mast;  3d,  at  a  point 
half  way  between  the  two  former. — 
The  heights  at  which  the  breadths  are 
taken  at  the  above  places,  are,  1st,  on 
a  level  with  the  deck ;   2nd,  on  a  level 


with  the  upper  surface  of  the  keelson  ; 
3d,  at  a  level  half  way  between  the 
two  former  positions.  To  find  the 
area  of  each  section,  the  half  of  the 
sum  of  the  upper  and  lower  measure- 
ments is  added  to  the  middle  measure- 
ment, and  this  sum  is  multiplied  by  the 
height  of  one  above  the  other ;  then 
half  the  areas  of  the  fore  and  after  sec- 
tion is  added  to  that  of  the  middle  sec- 
tion, and  this  sum  is  multiplied  by  the 
length  which  the  sections  are  apart 
from  each  other,  the  result  will  express 
in  burgos  cubic  feet  the  capacity  of 
the  part  of  the  hold  between  the  fore 
and  after  sections ;  and  it  still  remains 
to  add  the  spaces  between  these  and 
the  stem  and  stern-post :  these  are 
found,  without  any  considerable  error, 
by  multiplying  the  area  of  the  foremost 
section  by  half  its  distance  from  the 
stern  post.  The  room  occupied  by  the 
pumps  must  be  deducted  from  the  fore- 
going result,  in  order  to  obtain  the  fair 
quantity  of  space  filled  by  the  cargo. 
Having  thus  found  the  capacity  of  the 
hold  of  any  vessel  in  the  above  man- 
ner, in  burgos  cubic  feet,  it  is  to  be  di- 
vided by  41,61.779  feet  of  burgos. — 
In  Portugal,  for  single-decked  vessels, 
the  length  is  measured  from  the  cabin 
bulk-heads  to  the  forecastle  bulk-heads: 
the  depth  is  measured  from  the  upper 
surface  of  the  keelson  to  the  under  sur- 
face  of  the  beams  ;  the  extreme  breadth 


MARINE   AND    NAVAL    ARCHITECTURE. 


53 


of  the  deck  is  considered  the  breadth; 
the  continued  product  of  these  three  di- 
mensions will  give  the  contents  in  cu- 
bic feet,  which,  divided  by  57.726  gives 
the  tonnage.  In  vessels  having  two 
decks,  two  distinct  operations  are  per- 
formed, one  for  the  hold,  and  the  other 
for  the  middle  deck ;  for  the  hold,  the 
length  is  measured  from  the  heel  of  the 
bowsprit  to  the  stern-post ;  the  breadth 
is  the  extreme  breadth  of  the  upper 
deck,  deducting  two  feet ;  the  depth  is 
from  the  upper  surface  of  the  keelson 
to  the  under  surface  of  the  beams,  for 
the  middle  deck ;  the  length  is  con- 
sidered as  half  of  that  of  the  hold,  the 
other  half  being  allowed  for  cabins, 
&c.  ;  the  breadth  as  before,  and  for 
the  height  to  the  under  surface  of  the 
beams  of  the  upper  deck.  The  fore- 
going is  the  mode  at  Lisbon,  but  at 
Oporto,  the  length  of  the  vessel  is 
taken  from  the  second  timber  at  the 
bows  to  the  stern-post,  the  breadth 
at  the  widest  part,  from  the  inside 
of  each  bulwark  on  the  upper  deck, 
and  the  depth  from  the  upper  surface 
of  the  keelson  to  the  lower  surface  of 
the  beams  of  the  upper  deck  at  the 
main  hatch.  If  the  keelson  be  more 
than  the  ordinary  depth,  allowance  is 
made  accordingly — and  where  there  are 
two  decks,  the  thickness  of  the  lower 
deck  is  also  deducted  from  the  depth  ; 
the  length  is  multiplied  by  the  breadth, 


and  the  product  by  the  depth ;  this 
product  is  then  divided  by  96,  the  num- 
ber of  Portuguese  cubic  feet  contained 
in  a  ton,  and  the  result  is  the  tonnage 
of  the  vessel.  In  Naples,  the  vessel 
having  two  decks  is  measured  from 
one  end  to  the  other  over  all ;  the 
length  is  also  measured  from  the  after 
part  of  the  stem  to  the  rudder-port 
under  the  poop  ;  the  mean  of  these 
two  lengths  is  multiplied  by  the  ex- 
treme breadth  of  the  vessel.  The 
depth  is  then  taken  from  the  bottom 
of  the  well  to  the  lower  surface  of  the 
upper  or  poop  deck,  and  the  above 
product  being  multiplied  by  this  depth, 
and  divided  by  94,  gives  the  tonnage. 
For  single-decked  vessels,  the  tonnage 
is  found  by  multiplying  the  extreme 
length  by  the  extreme  breadth,  and 
the  product  by  the  extreme  depth,  di- 
vided by  94,  as  above.  In  the  Nether- 
lands, the  length  is  measured  on  deck 
from  the  stem  to  the  stern-post ;  for 
the  breadth,  the  hold  is  divided  into 
four  portions,  and  two  measurements 
taken  at  each  of  these  divisions — 1st, 
across  the  keelson,  on  a  level  with  the 
upper  surface  from  ceiling;  2nd,  the 
greatest  breadth  of  the  hold  at  each  di- 
vision ;  the  mean  of  these  six  meas- 
urements is  considered  the  breadth  ;  the 
depths  are  taken  at  each  of  (he  forego- 
ing points  of  division,  from  the  upper 
surface    of   the  keelson  to    the    low «  r 


54 


MARINE    AND    NAVAL    ARCHITECTURE. 


surface  of  the  upper  deck,  between  the 
beams,  and  the  mean  of*  these  three  is 
assumed.  The  length,  breadth  and 
depth,  are  then  multiplied  together,  and 
two-thirds  of  the  product  considered 
as  the  tonnage  ;  but  an  allowance  for 
provisions,  water,  cabin  and  ship-stores, 
varying  from  thirty  to  forty-five,  is  de- 
ducted from  the  depth  before  it  is  mul- 
tiplied by  the  length  and  breadth.  In 
Norway,  the  length  of  a  ship  is  taken 
from  the  afterpart  of  the  stem  to  the 
inner  part  of  the  stern-post,  dividing 
the  length  of  the  vessel  into  four  equal 
parts  ;  the  breadth  is  measured  at  each 
of  these  divisions.  The  depth  of  the 
vessel,  from  the  under  surface  of  the 
upper  deck  to  the  keelson,  to  be  taken 
at  the  above  three  points  of  division ; 
then  multiply  the  length  by  the  mean 
of  the  three  breadths,  and  the  product 
thereof  by  the  mean  three  depths  ;  the 
result  of  the  foregoing  is  divided  by 
242.1-2,  if  there  be  no  fractional  parts 
of  feet,  but  if  there  be,  the  calculation 
is  made  in  inches,  and  the  divisor  be- 
comes 322, 767;  the  result  thus  obtained 
being  the  burthen  of  the  vessel  in  wood- 
lasts,  of  4,000  Neva  pounds  each,  to 
reduce  into  commerce-lasts,  one  of 
which  is  equal  to  5,200  Neva  pounds,  it 
\ .  multiplied  by  10  and  divided  by  13. 
In  Russia,  the  length  of  the  keel  is 
taken  in  feet,  and  multiplied  by  the 
extreme  breadth  of  the  sheathing,  and 


the  product  multiplied  again  by  half 
the  breadth,  and  divided  by  94,  which 
gives  the  number  of  English  tons.  In 
the  United  States,  if  the  vessel  be 
double-decked,  the  length  is  taken 
from  the  forepart  of  the  main  stem  to 
the  afterpart  of  the  stern-post,  above 
the  upper  deck,  the  breadth  at  the 
broadest  part  above  the  main-wales, 
half  of  which  is  accounted  for  the 
depth;  from  the  length,  three-fifths  of 
the  breadth  is  deducted,  the  remainder 
is  multiplied  by  the  breadth,  and  the 
product  by  the  depth  :  this  last  product 
is  divided  by  95,  and  the  quotient  is 
deemed  the  true  contents  or  tonnage 
of  such  ship  or  vessel.  If  the  vessel 
be  single-decked,the  length  and  breadth 
are  taken  as  above ;  for  a  double- 
decked  vessel,  three-fifths  of  the 
breadth  are  deducted  from  the  length; 
the  depth  of  the  hold  is  taken  from  the 
under  side  of  the  deck-plank  to  the 
ceiling  in  the  hold  ;  these  are  multiplied 
and  divided  as  aforesaid,  and  the  quo- 
tient is  the  tonnage.  The  foregoing 
is  the  government  rule,  but  at  Phila- 
delphia and  New-Orleans  there  is  a 
mode  of  measurement  called  carpen- 
ters' tonnage.  The  Philadelphia  rule 
for  vessels  with  one  deck — multiply  the 
length  of  the  keel  by  the  breadth  of  the 
main-beam,  and  the  product  by  the 
depth  ;  divide  this  second  product  by 
95.      For  double-decked    vessels,   take 


MARINE    AND    NAVAL    ARCHITECTURE. 


55 


half  of  the  breadth  of  the  main-beam 
for  the  depth,  and  work  as  for  a  single- 
decked  vessel.  At  New-Orleans,  the 
mode  in  use  is  as  follows :  Take  the 
length  from  the  stem  to  the  afterpart 
of  the  stern-post  on  the  deck;  take  the 
greatest  breadth  over  the  main-hatch, 
and  the  depth  from  the  ceiling  of  the 
hold  to  the  lower  surface  of  the  deck; 
at  the  main-hatch  from  the  length  de- 
duct three-fifths  of  the  breadth,  multi- 
ply the  remainder  by  the  actual  breadth 
and  depth,  divide  by  95,  if  the  vessel 
be  single-decked,  but  if  the  vessel  be 
double-decked,  half  of  the  breadth  of 
the  beam  is  considered  as  equivalent  to 
the  depth,  and  is  multiplied  accordingly. 
The  Tonnage  Committee  having1 
embodied  in  their  report  the  tonnage 
laws  of  all  the  principal  commercial  na- 
tions, the  discrepancy  is  at  once  ren- 
dered apparent.  They  recommend  in 
their  report,  as  a  basis  for  the  new  law, 
that  the  whole  internal  capacity  be 
measured;  which,  being  under  cover 
of  prominent  decks,  may  be  available 
for  stowage.  They  have  given  a  short 
and  easy  rule  for  determining  the  ca- 
pacity, with  such  accuracy,  that  if  the 
whole  mercantile  marine  were  meas- 
ured by  the  new  process,  the  total 
registered  tonnage  would  be  very  little 
altered.  But  they  recommend,  that 
no  ship  already  registered,  shall  be  re- 
measured,  unless  at  the  request  of  the 


owner.  The  accurate  estimation  of 
the  tonnage  of  a  ship  is  a  very  difficult 
problem  indeed  ;  and  it  is  indispensable, 
that  any  system  to  be  adopted  in  prac- 
tice, be  not  very  complex :  for  if  so,  it 
will  either  be  wholly  inapplicable,  or  it 
will  be  sure  to  be  incorrectly  applied. 
The  relative  capacities  of  ships  are  de- 
termined very  nearly  by  this  method, 
that  is,  within  little  more  than  four  or 
five  per  cent,  generally,  though  in  ex- 
treme cases,  the  difference  may  amount 
to  ten  or  twelve  per  cent.  ;  this,  how- 
ever, is  insignificant,  when  compared 
with  the  errors  so  common  under  the 
former  rule.  The  divisor,  by  which 
the  cubic  content  is  reduced  to  ton- 
nage, was  adopted  merely,  that  while 
the  reputed  tonnage  of  nearly  all  kinds 
of  vessels  would  be  corrected  by  the 
new  rule,  the  total  registered  tonnage 
of  the  kingdom  might  remain  unal- 
tered  :  thus,  virtually  substituting  ca- 
pacity or  cubic  feet  for  tons,  or  internal 
for  external  capacity.  By  the  new 
method,  the  dues  paid  on  tonnage  are 
proportioned  to  the  capacities  of  the 
vessels  ;  and  as  no  advantage  is  gained 
in  these  respects  by  defective  fori  us 
consequent  upon  disproportionate  di- 
mensions, a  marked  improvement  in 
merchant  vessels  has  followed  the  pas- 
sage of  the  law  in  1835.  The  author 
is  disposed  to  look  through  the  vista 
of  perspective    futurity   to   the    period 


56 


MARINE    AND    NAVAL    ARCHITECTURE, 


when  the  commerce  of  the  United 
States  will  be  relieved  from  the  present 
heterogeneous  code.  With  a  slight 
amendment,  the  English  law  would  be 
well-suited  to  the  wants  of  the  United 
States.  The  clause  assuming  the  ves- 
sels to  have  a  poop,  or  half-deck,  should 
read  thus  :  "  If  any  vessel  have  a  half- 
deck,  poop,  or  weather-proof  house, 
above  the  upper  or  main-deck,  or  break 
in  the  main  or  upper-deck,  &c."  It  is 
notoriously  true,  that  almost  every  ship 
that  is  now  built,  and  being  built,  has 
a  house  upon  deck ;  and  it  is  some- 
times the  case,  that  in  the  distribution 
of  deck  surface,  direct  reference  is  had 
to  the  evasion  of  the  laws  of  this  or 
some  other  country.  Vessels  have  been 
built  in  this  city,  and  so  arranged,  that 
at  pleasure  they  could  be  converted 
from  a  bark  into  a  brig  ;  the  object 
was  the  evasion  of  measurement  of  the 
length  of  the  vessel,  which  was  set 
down  as  extending  from  the  bow  to 
the  end  of  the  tiller  ;  thus,  by  removing 
the  mizzen-mast,  and  substituting  a 
long  tiller  for  a  short  one,  before  en- 
tering port,  some  advantage  was 
gained,  where  such  laws  of  measure- 
ment existed.  It  must  be  apparent  to 
the  discerning  mind,  that  any  mode  of 
measurement  other  than  the  whole  ca- 
pacity is  subject  to  evasion ;  that  to 
set  apart  any  part  of  the  ship  for  pas- 
sengers, stores,  or  even  a  galley  for  the 


cook,  is  only  equivalent  to  an  extension 
of  those  accommodations.  While  we 
measure  ships,  and  regard  that  meas- 
urement as  a  standard  for  the  payment 
of  dues,  the  whole  capacity  should  be 
measured ;  but  the  author  hesitates 
not  to  say,  that  the  world  never  com- 
mitted a  greater  error  in  commercial 
economy,  than  when  they  first  deter- 
mined the  existence  of  a  law  for  levy- 
ing dues  according  to  tonnage  :  be  the 
law  of  tonnage  founded  on  weight,  di- 
mensions, or  capacity,  in  every  case  it 
operates  as  a  check  to  the  most  im- 
portant manufacture  of  the  country. 
In  order  that  any  nation  may  have 
free  exercise  for  its  skill,  capital  and 
enterprise,  that  nation  must  not  be 
bound  by  injurious  laws.  Our  govern- 
ment, by  continuing  in  force  laws  so 
detrimental  to  commerce,  deprives  her- 
self of  that  aid  so  essential  in  the  event 
of  a  rupture  with  a  foreign  power. — 
Our  European  packets  possess  every 
other  (] imbrication  than  that  of  proper 
dimensions  for  rendering  efficient  aid 
to  what  has  been  termed  the  right  arm 
of  our  national  defence.  Our  tonnage 
laws  have  a  direct  bearing  on  the  di- 
mensions of  every  vessel  built  in  the 
United  States  having  more  than  one 
deck.  But  the  ship-owners  proceed 
with  caution,  lest  the  magnitude  of  the 
mischief  provoke  national  legislation. 
Leaving    the    tonnage    laws  in   the 


MARINE    AND   NAVAL    ARCHITECTURE. 


57 


hands  of  those  that  made  them,  we 
shall  endeavor  to  analyze  the  laws  of 
resistance. 

A  variety  of  theories  have  been  pro- 
mulgated by  men  of  science,  for  over- 
coming what  the  author  has,  in  com- 
mon with  his  fellow-mechanics,  called 
resistance  ;  each  in  their  turn  produ- 
cing what,  in  the  projector's  opinion, 
seemed  to  be  the  most  tangible,  the 
most  conclusive.  Some  have  absorbed 
nearly  all  the  retarding  forces  into  the 
power  of  inertia,  and  have  lost  sight  of 
all  other  influences  ;  others  have  com- 
puted various  other  opposing  forces, 
and  have  assigned  to  inertia  but  a 
small  place  in  the  catalogue ;  some 
have  even  ventured  to  delineate  the 
only  proper  shape,  and  to  furnish  pro- 
portionate dimensions,  by  deductions 
drawn  from  the  planetary  world  for 
all  vessels  adapted  to  the  purposes  of 
commerce.  But  the  reader,  who  is 
adding  practical  knowledge  to  the  stock 
of  information  he  may  have  gained 
from  theorists,  will  discover,  that  nei- 
ther the  earth's  path,  or  the  path  of 
any  other  planet,  will  furnish  him  with 
a  stereotyped  edition  of  shapes  or  di- 
mensions ;  that  there  is  a  variety  of 
influences  known  only  to  practical 
men,  that  retard  our  progress  in  navi- 
gating the  ocean.  The  lubricity  of 
the  element  we  navigate,  would  lead 
many  to  conclude  that  friction  existed 


only  in  name ;  but  who,  among  the 
mechanical  portion  of  the  commercial 
world,  does  not  know,  that  by  copper- 
ing a  vessel,  we  increase  her  speed,  or 
that  by  coating  the  bottom  with  var- 
nish and  black  lead,  we  augment  the 
velocity  with  the  same  power.  These, 
with  other  facts  in  the  possession  of 
the  commercial  world,  teach  us,  that 
although  water  is  frictionless,  itself 
considered,  yet,  when  brought  into  jux- 
taposition with  a  floating  body  or  ves- 
sel, friction  forms  a  considerable  part 
of  the  opposing  force. 

Resistance  has,  from  time  immemo- 
rial, furnished  not  only  an  extensive 
field  for  operative  genius  and  skill  in 
every  age,  but  has  also  furnished  the 
motive  power  for  overcoming  the  same, 
and  may  emphatically  be  termed  the 
main-spring  in  mechanics.  The  great 
Syracusan  philosopher  required  but  an 
amount  of  resistance  commensurate 
with  the  friction  of  his  levers  added  to 
the  weight  of  the  world,  and  he  would 
have  had  a  platform  for  his  fulcrum. 
It  may  be  regarded  as  an  axiom,  or  a 
universal  law,  that  action  and  re-action, 
when  applied  to  solid  bodies,  are  com- 
mensurate quantities.  The  laws  of 
motion  are  deducible,  and  may  be 
known  under  three  general  heads : — 
The  first,  an  inherent  property  of 
matter  called  inertia,  and  known  as 
that    law   of  the    material    world,   by 


58 


MARINE    AND    NAVAL    ARCHITECTURE 


which  all  bodies  are  absolutely  passive 
or  indifferent  to  a  state  of  rest  or  mo- 
tion, and  would  forever  continue  in 
the  same  state,  unless  disturbed  by 
some  external  force,  commonly  called 
resistance.  According-  to  this  law,  the 
heavenly  bodies  preserve  their  progress- 
ive motions  undiminished  in  those  re- 
gions which  are  void  of  all  resistance  ; 
the  same  law  would  keep  the  boy's  top 
forever  in  motion  with  an  endless  revo- 
lution, were  it  not  impeded  by  the  air, 
and  the  friction  produced  by  its  point 
on  the  plane  on  which  it  moves.  A 
ball  discharged  from  a  cannon  would 
forever  persevere  in  its  motion,  were  it 
not  retarded  by  the  resistance  of  the 
atmosphere,  and  the  operating  influ- 
ence of  gravity. 

The  second  general  law  is  found 
when  a  change  of  motion  is  required 
which  must  be  proportional  to  the 
moving  force  by  which  it  is  produced, 
and  the  change  will  be  made  in  the 
line  of  direction  in  which  that  force  is 
applied  ;  hence,  it  follows,  that  motion, 
thus  generated,  is  in  right  line  with  a 
velocity  equal  to  the  degree  of  im- 
pulse, and  the  course  of  a  body  in  mo- 
tion can  only  be  altered  by  a  fresh  im- 
pulse, and  is  then  compounded  of  its 
own  velocity  and  the  impelling  force ; 
that  is,  the  body  will  be  either  accele- 
rated or  retarded  in  the  same  or  a 
right-lined  direction,  in   proportion  to 


the  compound  force  of  the  two  im- 
pressions. In  like  manner,  if  a  ship 
be  sailing  before  the  wind,  the  impulse 
is  in  direct  line,  and,  as  a  consequence, 
the  resistance  to  be  overcome  by  the 
two  fluids  is  absolute  ;  and  the  resist- 
ance met  by  the  ship  in  the  thud  that 
sustains  her,  and  through  which  she 
passes,  is  only  equal  to  the  resistance 
met  by  the  sails,  and  communicated  to 
the  moving  ship.  If  a  ship  be  sailing 
before  the  wind,  due  east,  if  you  please, 
at  the  rate  of  eight  miles  per  hour,  and 
a  current  setting  to  the  north,  at  the 
rate  of  four  miles  an  hour,  the  vessel 
is  driven  between  these  two  acting- 
forces  compounded  at  the  rate  of 
nearly  nine  miles  per  hour. 

The  third  law  of  motion  teaches  us 
that  action  and  re-action  are  always 
equal  and  contrary  ;  or  the  action  of 
two  bodies  on  each  other,  or  on  a  third 
body  remaining  passive,  is  always  equal, 
but  in  contrary  directions.  Thus, 
when  a  horse  draws  a. load,  the  power 
of  the  horse  is  diminished,  or  the  ani- 
mal drawn  back,  with  a  force  equal  to 
that  which  sets  the  load  in  motion  ;  for 
if  the  weight  of  the  load  be  increased, 
until  it  is  equal  to  the  strength  of  the 
horse,  it  will  remain  at  rest,  though 
the  whole  force  of  the  animal  be  in  ac- 
tion. If  a  load-stone,  and  a  piece  of 
iron  of  equal  weight,  be  suspended  by 
strings  near  each    other,  the    mutual 


MARINE  AND  NAVAL  ARCHITECTURE. 


59 


force  or  attraction  between  them  will 
cause  an  equal  action,  and  the  two 
bodies  will  leave  their  respective  posi- 
tions with  an  equal  impulse  and  velo- 
city, and  meet  in  a  point  equally  distant 
from  each.  If  the  bodies  be  unequal, 
they  will  meet  in  a  point,  whose  dis- 
tance from  the  bodies  will  be  recipro- 
cally proportioned  to  the  difference  of 
the  powers.  If  two  floating  vessels, 
of  equal  magnitude  and  density,  and, 
as  a  consequence,  of  equal  displace- 
ment, and,  in  addition,  possessing  an 
equal  amount  of  resistance,  be  attached 
to  each  other  by  a  rope,  the  vessels 
being  at  some  distance  from  each 
other,  a  force  applied  to  the  rope  in 
either  vessel  will  mutually  draw  them 
together  with  an  equal  velocity,  until 
they  meet  in  a  point  equidistant  from 
their  first  position  ;  but  if  the  amount 
of  resistance  be  unequal,  even  though 
the  magnitude  and  weight,  or  displace- 
ment of  the  vessel,  be  equal,  they  will 
not  meet  in  a  point  equidistant  from 
each  other,  but  the  vessel  possessing 
the  least  amount  of  resistance  will  ad- 
vance the  farthest ;  and  the  compara- 
tive sailing  qualities  of  vessels  may  be 
tested  in  port  as  well  as  at  Sea,  provi- 
ded the  propelling  power  is  equally 
well  applied  in  both  vessels.  Thus,  it 
may  be  readily  determined  which  of 
two  vessels  possesses  the  greater  amount 
of  resistanee,  by  placing  I  hem  any  dis- 


tance apart,  in  smooth  water,  where 
there  are  no  currents  ;  then  connecting 
them  with  a  rope,  and  applying  a  force 
to  one  end  of  the  rope  on  either  vessel, 
a  buoy  being  placed  equidistant  from 
each  vessel,  it  will  be  readily  deter- 
mined which  vessel  arrives  at  the  buoy 
first  ;  the  same  possesses  the  least 
amount  of  resistance,  or  is  best  adapt- 
ed to  overcome  the  inertia  at  that  line 
of  flotation,  and,  as  a  consequence, 
that  vessel  would  sail  the  faster,  other 
things  being  equal. 

As  the  whole  doctrine  of  resistance 
in  fluids  is  based  on  the  equilibrium 
of  the  same,  we  shall  here  give  a 
general  view  of  the  leading  principles 
of  this  branch  of  equilibriated  gravity 
in  fluids. 

Resistance  comprises  all  the  influ- 
ences that  directly  and  indirectly  op- 
pose our  progress  in  navigating  the 
ocean,  and  may  be  divided  into  its 
several  departments  ;  inertia  being  the 
first  and  most  powerful.  The  power 
of  attraction,  although  seemingly  of  a 
negative  character,  forms  a  large  bulk 
of  the  resistance  to  be  overcome  in 
navigating  our  rivers.  Attraction  is 
the  cause,  power  or  principle,  by 
which  all  bodies  mutually  lend  to- 
wards each  other.  This  universal 
principle  may  be  considered  as  one  of 
the  first  agents  of  nature  in  all  her 
operations — the  whole  universe  is  gov- 


GO 


MARINE    AND    NAVAL    ARCHITECTURE. 


erned  by  its  influence — and  yet,  after 
endless  opinions,  some  of  its  properties 
are  still  concealed  in  the  bosom  of  na- 
ture. We  clearly  see  the  effects  of 
attraction,  and  decide  on  its  laws ;  but 
human  ingenuity  has  not  been  able  to 
penetrate  its  principles,  or  to  fathom 
its  essence.  It  was  considered  by  that 
profound  thinker,  Sir  Isaac  Newton, 
as  a  power  proceeding  from  bodies  in 
every  direction,  which  decreases  in 
energy  or  effect,  in  proportion  as  the 
squares  of  the  distance  from  the  body 
increase ;  that  is,  at  any  given  dis- 
tance, it  will  be  four  times  as  great  as 
at  twice  that  distance,  and  nine  times 
as  great  as  at  three  times  the  distance, 
and  so  on  in  like  proportion.  The 
formation  of  the  element  we  navigate, 
and  of  all  bodies,  arises  from  the  adhe- 
sion or  attraction  of  the  particles. — 
Who,  of  our  readers,  has  not  often 
witnessed  its  effects  upon  vessels  sail- 
ing beside  each  other  ?  An  inferior  sail- 
ing vessel  is  enabled,  by  this  universal 
law,  to  keep  pace  with  her  faster  sail- 
ing rival  for  many  miles,  until,  by  some 
sudden  freak,  the  superior  sailing  ves- 
sel is  enabled  to  break  the  seemingly 
attractive  charm,  and,  by  increasing 
the  distance,  diminishes  the  attraction. 
Or,  who  has  not  often  witnessed  a  rival 
steamboat,  holding  at  a  convenient 
distance  a  much  faster  boat,  by  the 
power  of  attraction  in  the  fluid  they 


navigate  ?  How  often  have  our  readers 
witnessed  the  effects  of  crossing  a  bar 
in  a  river,  or  of  a  near  proximity  to  a 
shoal,  or  to  the  shore,  on  the  speed  of 
the  vessel,  and  the  effect  upon  the 
water  in  the  increased  disturbance, 
caused  by  the  addition  of  this  attract- 
ive power  to  the  resistance  produced  by 
other  of  nature's  laws.  This  law  has 
different  divisions,  and  in  those  divi- 
sions, different  modifications.  The 
principal  attractive  forces  known  in 
the  material  world,  are,  cohesive,  elec- 
trical, magnetical,  and  gravitating  ;  the 
former  and  latter  are  those  which 
should  form  a  branch  of  the  science 
of  marine  and  naval  architecture,  in- 
asmuch as  a  very  material  portion  of 
the  absolute  resistance  met  by  floating 
bodies  is  found  to  be  made  up  of  co- 
hesive and  gravitative  attraction.  A 
few  examples  Avill  serve  to  illustrate 
the  connection  existing  between  them  : 
Cohesion  is  the  resistance  witnessed 
on  attempts  to  separate  bodies,  and  is 
most  powerful  in  the  point  of  contact, 
or  where  the  particles  touch  ;  at  a  little 
distance  it  becomes  considerably  less, 
and  when  the  particles  are  still  further 
removed,  the  effect  is  rendered  insensi- 
ble ;  the  ratio,  as  found  by  Newton, 
has  been  already  given. 

The  cohesion  of  particles  of  small 
bodies  ;may  be  shown  by  a  variety 
of   amusing   experiments.      Take   two 


MARINE    AND    NAVAL    ARCHITECTURE. 


61 


musket  balls,  cut  away,  say  one-third 
of  the  bulk  of  each,  thus  forming 
*  planes,  which  should  be  made  even,  or, 
as  the  carpenters  would  term  it,  (with- 
out winding,)  press  the  two'  flat  sur- 
faces together,  and  twist  the  bullets  as 
they  are  pressed  with  the  fingers,  the 
plane  will,  by  this  means,  be  worn  per- 
fectly smooth  and  even  ;  the  parts  thus 
in  contact  will  adhere,  or  be  attracted 
by  a  cohesive  force  that  will  resist  a 
power  of  near  fifty  pounds  weight  to 
separate  them  ;  by  this  means,  the  air 
is  expelled  from  between  the  planes, 
and  a  greater  number  of  parts  or  par- 
ticles brought  into  contact;  as  the 
formation  of  bodies  arises  from  the  ad- 
hesion or  attractive  properties  of  the 
particles  of  matter.  If  the  metal  in 
the  above  experiment  were  perfectly 
free  from  porosity,  and  the  planes  per- 
fectly level,  or  mathematically  even,  on 
joining  them  together,  the  parts  in  ad- 
hesion would  be  as  firm  and  insepara- 
ble as  any  other  parts  of  the  balls. — 
The  elasticity  of  the  air  which  is  con- 
tained in  the  interstices,  consequent 
upon  the  inequality  of  the  planes,  is 
the  power  that  is  perpetually  endeav- 
ouring to  rend  them  asunder.  The 
planes  of  bodies  can  adhere  only  when 
the  power  of  the  parts  in  contact  is 
greater  than  the  natural  gravity,  and 
the  elastic  power  of  the  air  contained 
between  them;   therefore,  the  cohesive 


force  is  proportional  to  the  number  of 
parts  that  touch  each  other.  Plates 
of  iron,  or  other  metals,  of  small  di- 
mensions, may  be  made  to  cohere  with 
such  force  as  would  require  the  united 
force  of  a  number  of  men  to  pull  them 
asunder.  Experiments  have  shown, 
that  plates,  not  more  than  two  inches 
in  diameter,  have  taken  a  force  of  950 
pounds  weight  to  separate  them.  In 
such  cases,  the  surfaces  have  been 
smeared  with  boiling  grease,  and  then 
left  to  cool  before  the  power  was  ap- 
plied ;  the  grease  serves  to  fill  up  the 
pores  of  the  surface,  and  bring  a 
greater  number  of  particles  in  contact 
with  each  other.  This  adhesive  power, 
or  property  in  the  particles  of  bodies, 
is  not  occasioned  or  aided  by  the  gravi- 
tating weight  of  the  atmosphere  ;  for 
it  is  found  by  experiment,  that  it  re- 
quires the  same  weight  to  separate 
them,  whether  joined  together  in  open 
air  or  in  vacuo.  The  author  has  wit- 
nessed experiments  of  a  similar  nature 
producing  the  most  wondrous  results. 
This  cohesive  law  governs  the  union 
of  iron  to  iron,  and  of  iron  to  steel, 
commonly  called  welding.  It  is  well 
known,  that  when  at  a  certain  degree 
of  temperature,  or  at  what  is  called  a 
white-heat,  two  pieces  of  iron  may  be 
brought  together,  and  the  fibres  of  one 
piece  driven  by  the  hammer  into  the 
pores  of  the  other,  and  thus,  the  air  is 


62 


MARINE  AND  NAVAL  ARCHITECTURE. 


not    only  excluded    by    filling    up  the 

pores.  I>iit  the  pieces  arc  actually  riv- 
eted together,  and  it*  the  work  is  prop- 
erly done,  is  as  substantial  as  any  other 
part  of  the  material. 

It  is  by  the  attraction  of  cohesion 
the  particles  of  a  fluid  or  liquid  arrange 
themselves  into  a  spherical  form,  and 
extend  their  influence  through  the 
same  channel  to  all  bodies  with  which 
they  come  in  contact.  If  a  piece  of 
board  be  laid  upon  the  surface  of  water 
when  in  a  state  of  rest,  it  will  require 
a  power  nearly  six  times  as  great  as  the 
weight  of  the  board,  to  take  it  up  per- 
pendicularly. These,  and  many  other 
facts  which  daily  occur  in  the  com- 
mon occupations  of  life,  serve  to  show 
the  universal  tendency  of  that  corpus- 
cular attraction  which  exists  between 
small  bodies,  and  which  teaches,  if  we 
will  be  taught  by  the  laws  of  nature, 
that  the  resistance  met  by  vessels  when 
operated  upon  by  a  propelling  force, 
can  be  augmented  and  diminished  in 
proportion  as  we  adhere  to,  or  depart 
from,  nature's  laws.  The  last  exam- 
ple, of  the  board,  will  teach  us  that  a 
flat  surface  meets  with  more  resistance 
than  a  convex  one;  thus,  the  longitu- 
dinally straight-sided  ship  below  water 
meets  with  more  resistance  from  the 
water  than  one  having  a  convex  side, 
other  things  being  equal  ;  this  is 
eqnalU  true  of  the  ship  Inning  straight 


section-lines  on  the  flat  of  the  floor  or 
bottom.     The  example  of  the   board 
may  illustrate   this   principle  still   far- 
ther, showing  that  the  board  present 
ing   a   flat   surface  to  the   fluid,   as  a 
consequence,  receives  the  impulse  of 
attraction  in  a  direction  opposite  to  the 
force  applied  to  lift  it ;   and  it  must  fol- 
low, that   force  directly  applied,  must 
be  more  effectual  than  force  obliquely 
or  diagonally  applied,  which  the  board, 
having  a  convex  surface,  avowedly  re- 
presents.     It   has  been  stated,  that  the 
law  of  attraction    has    different    divi- 
sions and  modifications.      The  wonders 
of  another  department  of  this  sovereign 
law  may  be  seen  in  capillary    attrac- 
tion, through   the    medium    of  which, 
liquids  ascend  the  contiguous  surfaces 
of  bodies.      This  term  is  generally  used 
to  denote  the  ascent  of  fluids  throuL'h 
small  pipes   or  tubes  that  compose  a 
considerable  part  of  the  animal  as  well 
as  the  vegetable  body.      By  these  tubes, 
as  various  in  their  number  as  they  are 
different  in  their  capacity,  nature  con- 
veys  nutriment  to  supply  the  most  dis- 
tant branches  of  vegetation,  where  it 
could  never  arrive  by  the  ordinary  mo- 
tion of  fluids.     The  extent  of  the  at- 
traction is  in  proportion  to  the  diameter 
of  the  tube,  that  is,  those  tubes  which 
are  the   smallest  raise   the   fluid  to  the 
greatest    height,   and  the    larger    to  a 
less  height,  in  a  reciprocal  proportion. 


MARINE   AND    NAVAL    ARCHITECTURE. 


63 


When  the  earth  receives  rain  on  its 
surface,  the  fluid  is  attracted  through 
all  the  internal  and  contiguous  parts, 
and  then  absorbed  by  the  roots  of  trees 
and  plants,  and  carried  from  thence  by 
capillary  attraction  to  the  most  ex- 
tended parts  through  the  multitudi- 
nous pores  contained  in  the  trunk  and 
branches.  It  is  by  capillary  attraction 
that  the  flaming  wick  of  a  lamp  is  sup- 
plied with  oil  from  the  reservoir  be- 
neath. By  a  knowledge  of  the  laws 
of  attraction,  we  fancy  we  see  the 
reason  why  A  attracts  B,  or  why  B  is 
compelled  to  follow  the  motions  of  A, 
when  connected  ;  but  when  two  dis- 
tinct bodies,  not  connected  by  any  visi- 
ble bond  of  union,  are  observed  to 
approach  one  another,  the  phenomenon 
seems  to  assume  a  greater  degree  of 
mystery,  from  our  being  no  longer  able 
to  perceive  any  mode  by  which  the  one 
body  can  act  on  the  other.  On  re- 
flecting, however,  on  the  constitution 
of  material  substances,  and  considering 
that  they  are  composed  of  distinct  par- 
ticles, which  there  are  many  reasons 
for  believing  are  not  in  contact  with 
each  other,  we  may  soon  satisfy  our- 
selves that  there  is,  in  reality,  as  much 
difficulty  in  conceiving  how  the  differ- 
ent particles  of  a  body  cohere,  or  act 
on  each  other  by  impulse,  as  in  con- 
ceiving how  one  body  can  be  the  cause 
of  motion   in  another  placed  at  a  dis- 


tance. A  remark  of  Maupertius  is  in 
perfect  keeping-  on  this  subject :  that  the 
manner  in  which  the  different  proper- 
ties reside  in  a  subject,  is  always  incon- 
ceivable to  us.  The  mass  of  mankind 
are  not  astonished  when  they  see  a 
body  in  motion  communicate  its  mo- 
tion to  other  bodies  ;  we  are  accus- 
tomed to  the  phenomenon,  which  pre- 
vents our  perceiving  in  it  anything 
marvelous.  But  philosophers  will  not 
readily  believe  that  an  impulsive  force 
is  more  conceivable  than  an  attractive 
one.  What  in  fact  is  this  impulsive 
force  ?  How  does  it  reside  in  bodies  ? 
Who  could  have  predicted  its  exist- 
ence before  seeing  the  bodies  impinge 
against  each  other?  The  existence 
of  other  properties  in  bodies  is  not 
more  clear.  In  what  way  does  impen- 
etrability and  the  other  properties  be- 
come joined  to  extension  ?  In  these 
there  will  always  be  mysteries  for  us. 
It  must  not,  however,  be  supposed,  that 
because  mankind  are  ignorant  of  the 
why  and  wherefore,  that  they  are  in 
reality  without  available  knowledge  of 
the  laws  that  govern  the  material 
world.  Philosophers,  without  any  re- 
ference to  the  question,  whether  the 
power  which  produces  that  tendency 
is  inherent  in  the  bodies,  or  consists  in 
the  expulsion  of  an  external  agent — 
they  regard  it  as  one  of  the  ultimate 
phenomena  to  which  the  analysis  of 


64 


MARINE  AND  NAVAL  ARCHITECTURE. 


. 


matter  leads.  Newton  himself,  partic- 
ularly cautions  his  readers  against 
supposing  that  there  is  really  an  at- 
tractive force  residing  in  the  centre  to- 
wards which  bodies  tend,  the  centres 
being  only  mathematical  points.  It 
will  doubtless  be  discovered,  from  what 
has  been  shown,  that  cohesive  attrac- 
tion forms  a  very  material  part  of  the 
resistance  met  by  floating  bodies,  and 
that  by  a  knowledge  of,  and  a  strict  ad- 
herence to  these  laws,  we  are  enabled 
to  modify  the  resistance  on  vessels,  and 
thus  the  advantages  of  science  blended 
with  practice,  are  made  manifest,  not 
only  to  the  thinking-man,  but  to  the 
casual  observer.  Mr.  Russell,  in  his 
experiments,  met  with  some  results 
which  are  said  to  be  of  great  value  to 
practical  men  on  the  general  problem 
of  the  resistance  of  a  fluid  to  a  solid 
body;  a  department  of  science  of  which 
the  mechanical  world  is  avowedly  igno- 
rant. The  assumption,  that  the  fluid 
impinging  against  a  solid,  or  the  solid 
against  the  fluid,  were  the  same,  or 
produced  the  same  results,  must  be  re- 
garded as  erroneous,  and  calculated  to 
mislead  the  inquirer  after  truth  ;  the 
solid  impinging  against  the  fluid,  not 
only  causes  a  greater  elevation  at  the 
surface,  but  a  greater  disturbance,  as  a 
consequence  beneath,  of  which  the 
surface  may  be  regarded  as  an  index ; 
that  the  diflerence,  however,  would  be 


much  less,  Mr.  Russell  himself,  per- 
haps, would  be  willing  to  admit,  when 
applied  to  vessels.  The  extreme  lu- 
bricity of  the  fluid  being  frictionless, 
must  of  necessity  materially  affect  any 
change  in  the  application  of  force. — 
Mr.  Russell  discovered  that,  the  sum 
total  of  the  resistance  on  the  anterior 
part  of  a  solid  was  found  in  the  wave 
generated  at  the  surface;  hence,  by 
this  hypothesis,  it  was  only  necessary 
to  find  the  force  required  to  generate 
that  wave,  and  the  resistance  was  de- 
termined ;  here,  again,  we  are  shown 
the  imbecility  of  science  without  prac- 
tical knowledge.  Had  Mr.  Russell 
known  that  vessels  have  been  built  in 
the  United  States  so  sharp,  longitudi- 
nally, that  at  a  speed  of  20  miles  per 
hour  they  did  not  generate  a  wave  on 
the  anterior  part,  he  would  have  hesi- 
tated before  launching  that  dogma 
upon  the  commercial  world.  It  will 
appear  manifest  to  the  thinking  man, 
that  a  vessel  moving  through  the  water 
must  communicate  a  motion  to  the 
particles  of  fluid  with  which  it  success- 
ively comes  in  contact.  The  quantity 
of  motion,  therefore,  communicated  to 
the  fluid,  is  necessarily  equal  to  that 
which  is  lost  by  the  vessel,  and  as  a 
consequence  is  the  measure  of  resist- 
ance. We  cannot  pursue  the  subject 
without  giving  an  exposition  of  the 
prominent    features  of  the    attracting 


MARINE    AND   NAVAL    ARCHITECTURE. 


65 


power  of  gravity,  and  the  pressure  of 
air,  as  forming  one  of  the  component 
parts  of  the  resistance  .to  be  overcome 
in  navigating  oceans,  lakes,  or  rivers. 
The  power  of  gravity  gives  the  same 
velocity  to  all  bodies,  the  truth  of 
which  may  be  tested  by  removing  the 
pressure  of  the  atmosphere.  Every 
square  foot  of  the  surface  of  the  ocean, 
as  well  as  the  earth,  sustains  a  pressure 
of  2,160  pounds  ;  this,  as  a  conse- 
quence, in  connection  with  gravitating 
and  cohesive  attraction,  forms  the  re- 
sistance at  the  surface  of  the  water ; 
hence,  it  follows,  that  in  the  ocean, 
where  neither  the  shore  nor  bottom  has 
any  influence  upon  the  vessel,  the  at- 
mospheric pressure  forms  a  large  por- 
tion of  the  resistance  to  be  overcome 
by  the  vessel,  apart  from  the  cohesive 
attraction  to  the  vessel  by  the  water. 
It  has  been  found,  that  at  an  angle  of 
six  degrees  on  the  line  of  flotation  from 
the  longitudinal  axis,  or  twelve  degrees, 
with  the  two  sides  united,  a  wave  was 
not  generated  at  the  highest  speed  that 
steamboats  have  attained  in  the  United 
States ;  thus,  it  is  plain,  that  on  the 
anterior  part,  the  resistance  was  within 
2.1(30  pounds  on  every  square  foot  of 
surface.  It  would  be  impossible  to 
tell,  however,  what  amount  of  resist- 
ance the  posterior  part  of  the  vessel 
meets,  while  the  method  of  modelling 
is  left  to  the   eye.      No  builder  knows 


whether  the  stern  is  adapted  to  the 
bow,  or  the  bow  to  the  stern ;  hence, 
it  follows,  that  men  of  science,  as  well 
as  men  of  practice,  must  forever  grope 
in  the  dark,  while  every  man  follows 
his  own  whims  in  shaping  vessels,  with- 
out reference  to  a  system  of  propor- 
tions in  accordance  with  the  laws  gov- 
erning the  elements.  Few  men  reflect, 
when  modelling  vessels,  that  the  after 
end  of  the  vessel  is  operated  on  when 
performing  her  evolutions,  by  a  force 
that  pulls  directly  aft,  and  that,  while 
propulsion  may  be  centered  at  one 
point,  the  resistance  cannot  be  so  lo- 
cated. It  has  been  already  set  down 
as  a  truism,  that  a  vessel  moving 
through  the  water,  communicates  a 
motion  to  the  same,  and  this  quantity 
of  motion  is  equal  to  that  which  is  lost 
by  the  moving  vessel.  As  vessels  are 
now  modelled  without  reference  to  a 
universal  system  of  proportions,  an  ap- 
proximation only  can  be  made  to  the 
direct  resistance ;  this  may  be  deter- 
mined on  the  anterior  part  of  the  ves- 
sel, and  will  answer  for  all  ordinary 
purposes,  in  the  following  manner  : — 
Multiply  the  area  (in  square  feet)  of 
the  immersed  portion  of  the  greatest 
transverse  section  by  645  the  weight 
of  one  cubic  foot  of  sea-water  ;  multi- 
ply that  product  by  the  velocity  in  feet 
per  minute  ;  this  product  multiply  by 
.4,  .5,  or  .6,  as  the  shape  of  the  ves- 


6G 


MARINE    AND    NAVAL    ARCHITECTURE, 


sel  may  require,  the  sharpest  vessel  re- 
quiring the  lowest  number,  while  the 
fullest  vessels  demanding  the  higher. 
An  example  will  perhaps  illustrate : 
Assuming  the  area  of  the  greatest 
transverse  section  to  be  892  feet,  and 
the  speed  to  be  set  down  at  fifteen 
miles  per  hour,  we  have  1320  feet 
per  minute  ;  thus,  we  have  1320  x 
892=  1177440x64 \  =75141120  x  .4  = 
30056448  -r-  2240  =  13418  tons,  138 
pounds  per  minute,  in  adverse  pressure 
or  resistance.  In  order  to  have  this 
resistance  or  pressure  constant,  the 
quotient  or  last  number  must  be  divi- 
ded by  60,  and  we  have  the  sum  of 
223  tons,  1420  pounds.  But  this 
amount  of  resistance  is  not  wholly  de- 
pendent upon  the  length  or  shape  of 
the  anterior  part  ;  the  amount  of  the 
propelling  power,  and  its  application, 
have  much  to  do  with  the  resistance  ; 
neither  does  it  follow,  that  the  same 
mean  angle  of  resistance  on  the  inte- 
rior  part,  with  the  same  area  of  great- 
est transverse  section  or  (g)  frame,  will 
attain  the  same  speed  with  the  same 
amount  of  propulsion.  There  is  a  defi- 
nite amount  of  speed  peculiar  to  every 
shape,  and  belonging  to  every  shape, 
and  beyond  which,  if  forced,  the  vessel 
will  not  go  without  hazard.  This 
principle,  the  author  is  aware,  has  not 
been  received  with  favour  ;  but  he  ven- 
tures to  assert  the  possibility  of  its  de- 


monstration. It  is  a  truism  at  once 
conceded,  that  an  increase  of  speed  is 
an  increase  of.  resist  a  nee,  where  no 
changes  have  been  made  to  diminish 
the  same;  the  resistance  is  found  at 
the  two  ends  of  the  vessel,  and  the 
power  applied  at  or  near  the  centre. 
Does  it  not  appear  quite  manifest,  that 
between  those  two  powers  the  vessel 
may  be  rent  into  fragments?  It  mat- 
ters not  how  strong  she  may  have  been 
built,  the  resistance  pressing  the  vessel 
aft,  and  the  power  pressing  forward, 
which  may  be  increased  to  thousands 
of  tons,  will  undoubtedly  crush  her  if 
increased  and  continued.  If  proof 
were  necessary,  abundant  may  be 
afforded  in  the  wholesale  failures  on 
steamboats,  from  which  little  appears 
to  have  been  learned.  There  are 
steamboats  running  on  the  Hudson 
River,  that  will  not  bear  the  power 
they  already  possess,  having  a  plumb- 
side,  a  hard  bilge,  and  a  flat  bottom,  at 
the  same  time  having  a  large  amount 
of  resistance  with  a  proportionate 
amount  of  power,  they  groan  beneath 
a  load  too  intolerable  to  be  borne ;  the 
effects  are  both  felt  and  seen,  particu- 
larly in  shoal  water,  where  it  not  uii- 
frequently  occurs,  that  steamboats 
ground  where  there  is  from  one  to 
two  feet  more  water  than  would  be 
required  to  float  them  when  in  a  state 
of  rest.      The   proper  form    or  shape 


MARINE    AND    NAVAL    ARCHITECTURE. 


67 


that  will  effectually  obviate  this  discre- 
pancy, will  appear  when  it  is  known 
that  the  direction  of  the  opposing  in- 
fluence, or  the  direction  of  the  resist- 
ance, is  met  at  right  angles  from  every 
part  of  the  immersed  surface  of  the 
vessel ;  hence  it  follows,  as  an  inevit- 
able consequence,  that  vessels  present- 
ing to  the  action  of  the  fluid  a  large 
area  of  flat  surface,  must,  in  propor- 
tion to  the  amount  of  that  surface, 
have  a  large  amount  of  direct  resist- 
ance. It  matters  not  as  far  as  the  ac- 
tion extends,  whether  the  flat  surface 
be  on  the  side  or  under  the  bottom, 
the  deductive  results  of  experiments 
already  shown  have  set  this  question 
at  rest,  the  prejudices  of  public  opin- 
ion to  the  contrary,  notwithstanding ; 
and  were  further  proof  required,  we 
have  only  to  point  to  the  steamboat 
New  World,  having  doubtless  a  greater 
amount  of  surface  perfectly  flat,  than 
any  other  vessel  near  the  sea-board  of 
the  western  world.  The  direction  of 
the  resistance  being  at  right  angles 
from  the  outside  surface,  it  follows, 
that  the  lines  usually  called  water- 
lines,  are  improperly  named,  being 
only  parallels  to  the  line  of  flotation, 
and  not  lines  of  resistance.  We  do  not 
mean  that  the  water  passes  in  the  di- 
rection of  lines  running  diagonally,  as 
such  course  would  indicate,  but  that 
the  spherical  motion  of  the    molecules 


are  thus  directed;  and  it  must  be  elearto 
the  thinking  man,  that  a  greater  num- 
ber of  particles  is  set  in  motion  on  a 
vessel  having  a  certain  surfaced  area 
of  displaced  fluid,  and  also  a  greater 
proportion  of  flat  surface,  than  another 
having  less,  in  other  respects  equal  ; 
those  disturbed  particles  furnish  a  reg- 
ulating medium  at  the  stern  of  the  ves- 
sel, and  the  extent  of  the  disturbance 
determines  the  amount  of  speed,  inas- 
much as  the  vessel,  by  her  shape,  fur- 
nishes more  or  less  cohesive  attraction, 
and  in  the  proportion  of  the  cohesion 
is  the  speed  of  the  vessel,  the  one 
having  the  least  is  found  to  be  the 
fastest.  This  may,  to  many,  seem  pa- 
radoxical, inasmuch  as  some  of  our 
coasting  vessels  are  remarkably  fast 
sailers,  and  are  perfectly  flat,  (hence,  it 
seems  to  follow,  that  theory  and  prac- 
tice disagree.)  It  will  appear  clear 
upon  a  moment's  reflection,  that  all 
science  in  modelling  vessels  must  be 
based  upon  the  equilibrium  of  fluids, 
and  all  systems  void  of  this  inherent 
quality,  must  be  spurious,  and  will 
eventually  fall  to  the  ground.  It  mat- 
ters not  in  what  direction  the  vessel 
parts  the  water;  if'a  light  draught  of 
water  is  desirable,  it  may  be  obtained, 
as  in  the  sloop  of  our  rivers,  or  as  in 
the  steamboats.  It  is  not  the  draught 
of  water,  or  the  angle  of  rise  on  the 
transverse  section,  that  exhibits  those 


68 


MARINE    AND    NAVAL    ARCHITECTURE. 


objectionable  features  so  detrimental  to 
speed,  but  tbe  perfectly  flat  plane  pre- 
sented tor  attractive  cohesion.  AVater, 
as  has  been  observed,  is  a  frictionless 
body,  hence,  the  manifest  deductive 
principle,  were  there  no  other,  that 
at  the  least  inclination  or  disturb- 
ance, the  efforts  to  be  relieved  of 
the  pressure  are  sudden  and  irregular, 
and  that  a  sheet  of  water  below  its 
level  at  the  surface  cannot  be  held 
with  a  steady  pressure  when  that  sheet 
is  in  the  form  of  a  plane ;  this  truth  is 
recognised  even  by  the  school-boy, 
who  plays  with  his  boat  in  the  gurgling 
brook.  We  have  but  to  reflect  that 
the  direction  of  the  forces  are  parallel 
on  the  flat  bottom  or  side,  and,  as  a 
consequence,  it  is  as  easy  to  move  the 
sheet  of  fluid  in  one  direction  as 
another ;  hence,  when  relief  is  ob- 
tained from  the  pressure,  all  the  mole- 
cules move  in  the  direction  of  the  least 
pressure,  and  as  a  consequence,  the 
whole  mass  presenting  the  flat  surface 
moves  at  once,  and  in  the  same  direc- 
tion, disturbing  all  the  contiguous 
particles  in  a  greater  degree  than  they 
could  under  other  circumstances  have 
been  disturbed  ;  thus  we  can  philosoph- 
ically arrive  at  the  reason  why  a  steam- 
boat having  a  greater  area  of  flat  bot- 
tom than  another,  will  ground  in  shoal 
water,  while  another  having  less  will 
pass  clear,   drawing  more  water  than 


the  first  ;  the  attrition  of  so  many  mo- 
lecules at  the  same  time  from  the  bot- 
tom of  the  vessel  and  the  bottom  of  the 
river,  causes  an  augmentation  of  pres- 
sure and  disturbance  ;  consequently,  a 
commensurate  loss  of  buoyancy,  and 
the  particles  being  unequally  pressed, 
seek  an  equilibrium  around  the  vessel 
rather  than  under  her  ;  whereas,  had 
the  vessel  presented  no  perfectly  flat 
surface,  but  the  lines  gradually  rising 
in  every  direction,  so  that  the  direction 
of  the  forces  would  not  have  been  par- 
allel, it  will  be  clearly  perceived  that 
the  sheet  forward  of  the  greatest  trans- 
verse section  could  not  have  found 
an  equilibrium  by  passing  aft  without 
encountering  a  still  greater  pressure, 
inasmuch  as  the  ®  would  be  the  lowest, 
and  the  surface  forward  would  be  more 
elevated  than  the  sheet  aft ;  but  the 
great  and  universal  law  remains  yet  to 
be  described.  Inasmuch  as  all  and 
every  molecule  of  the  fluid  is  spherical, 
and  revolves  around  its  own  centre,  so 
every  molecule  is  least  disturbed  by 
appropriating  a  line  of  direction  to  it- 
self alone  ;  the  motion  of  the  molecules 
thus  directed  prevents  their  crowding 
on  each  other,  and  upon  this,  the 
whole  theory  not  only  of  equilibriated 
gravity  in  fluids  but  of  resistance  rests  ; 
whether  from  cohesive  attraction  or 
from  attrition.it  all  centres  in  this  uni- 
versal  law.     But  again,  we  may  follow 


MARINE    AND   NAVAL    ARCHITECTURE, 


69 


this  subject  farther,  perhaps,  with  profit 
to  our  readers,  by  showing  the  results 
or  the  effects  of  an  extensive  area  of 
flat  surface  on  some  of  our  steamboats  ; 
the  biljje  connecting  the  side  with  the 
bottom  being-  short,  the  consequence 
is,  that  but  a  small  sheet  of  water  passes 
between  the  wheel  and  the  edge  of  the 
flat  of  the  bottom  ;  this  column  (for  wa- 
ter may  be  so  considered,  the  pressure 
being  the  same  horizontal  as  vertical) 
being  pressed  by  the  sheet  under  the 
bottom,  and  attracted  by  the  water- 
wheel,  gives  place  to  the  unequal 
pressure,  and  is  filled  up  by  the  sheet 
below;  and  thus  a  continual  current  is 
formed  while  the  wheel  is  in  motion ; 
and  this  current  diminishes  the  buoy- 
ancy very  materially,  and  that  too,  in 
the  very  place  it  is  most  needed,  under 
the  engine ;  thus,  it  will  be  perceived, 
that  the  means  adopted  to  sustain  the 
engine,  support  the  vessel,  and  keep 
her  in  proper  shape,  are  the  very  cause 
of  her  being  broken-backed,  and  set- 
tling down  under  the  engine  :  a  fact 
too  well  known  to  be  questioned,  the 
cause  of  which  has  been  sought  only 
among  the  many  false  notions  of  the 
age.  It  is  a  well-known  fact,  that 
millions  of  dollars  have  been  spent  in 
this  city  alone  on  wholesale  experi- 
ments on  steamboats,  on  which  the 
projectors  have  given  the  clearest  evi- 
dence of  their  blind  adherence  to  pre- 


cedent, and  that  they  had  rather  guess 
at  what  they  want,  even  though  they 
should  be  compelled  to  pay  for  the 
second  effort  thousands  of  dollars.  All 
parties  concerned  in  these  wholesale 
blunders  have  become  so  accustomed 
to  this  mode  of  piecing  and  patching 
steamboats,  that  it  seems  to  be  regard- 
ed as  unavoidable  ;  and  if  a  company 
or  an  individual  is  so  fortunate  as  to 
obtain  a  boat  that  req uires  no  altera- 
tions, they  or  he  is  congratulated  on 
their  success  in  securing  the  services 
of  men  who  have  guessed  so  near. — 
Science,  or  the  principles  of  philoso- 
phy, seem  to  have  been  set  aside  alto- 
gether, as  unworthy  of  the  Anglo- 
Saxon  race.  Public  opinion  has  been 
melted  in  the  crucible  of  precedent,  and 
moulded  into  a  bundle  of  prejudices. 
Were  steamboat  companies  to  unite  in 
this  matter,  and  continue  experiment- 
ing on  the  same  boat,  they  might  ar- 
rive at  something  tangible ;  but  this 
would  bespeak  a  want  of  knowledge 
that  they  are  unwilling  to  admit. 

Resistance  presents  itself  to  the  mind 
of  the  mechanic  in  other  forms,  and  is 
known  by  other  names  than  those  al- 
ready enumerated.  All  the  force  op- 
posing the  vessel's  progress  is  abso- 
lute resistance,  whether  met  on  the 
bow  or  on  the  stern.  On  sailing  ves- 
sels there  are  two  kinds  of  resistance 
that  steamboats  do  not  encounter:  the 


70 


MARINE    AND    NAVAL    ARCHITECTURE 


first  is  called  lateral  resistance,  or  the 
opposing  force  which  the  vessel  pre- 
sents to  drifting  to  leeward,  at  right- 
angles,  or  at  any  other  angle  with  her 
course.  This  resistance  is  unlike  other 
retarding  forces  ;  and  a  vessel  cannot  he 
said  to  he  a  fair  sailer  unless  she  possess 
a  proportionate  degree  of  lateral  re- 
sistance ;  inasmuch  as  a  loss  of  late- 
ral resistance  amounts  to  a  corres- 
ponding loss  of  speed  ;  for  it  follows  as 
an  inevitable  consequence,  that  all  the 
propulsive  power  expended  on  the  lee- 
way would  he  added  to  the  head-way 
were  the  vessel  to  make  no  lee-way ; 
in  other  words,  were  the  absolute  re- 
sistance converted  into  lateral,  in  a 
given  time  the  vessel  would  be  farther 
advanced  in  her  onward  course,  the 
propulsive  power  remaining  unchanged. 
It  does  not,  however,  follow,  that  the 
vessel  having  the  most  lateral  resist- 
ance, has  also  the  least  absolute ;  it 
not  unfrequently  happens,  that  a  large 
amount  of  both  is  found  in  the  same 
vessel.  The  second  and  last  denomi- 
nation of  resistance  that  is  not  peculiar 
to  steamboats,  and  only  applicable  to 
sailing  vessels,  is  consequent  upon  the 
leverage,  and  the  inequality  of  the  lines 
of  immersion  and  emergence  ;  that 
part  of  the  resistance  consequent  upon 
the  leverage  would  indeed  be  small, 
were  the  centre  of  the  propulsive 
power  in   all  cases  in   its  proper  loca- 


tion ;  but  when  ships  that  draw  an 
equal  draught  of  water  when  leaving 
port,  are  found  from  one  to  three  feet 
by  the  head  at  sea,  we  are  led  to  con- 
elude  that  the  distribution  of  the  pro- 
pulsive power  has  been  improperly 
made;  the  inequality  existing  between 
the  lines  of  emergence  ami  immersion 
is  to  some  extent  unavoidable,  hut  as 
far  as  may  be,  they  can  be  equalized 
with  great  advantage  to  the  vessel. — 
Experiments  have  clearly  indicated, 
that  by  rendering  the  mean-angle  of 
resistance  more  acute  on  the  anterior 
part,  the  greatest  transverse  section 
may  be  located  farther  aft,  and  the 
lines  of  resistance  on  the  after-body 
swelled  out  to  advantage  for  speed  or 
stability.  But  this  augmentation  of  dis- 
placement on  the  posterior,  and  a  di- 
minution on  the  anterior  parts,  should 
be  distributed  very  differently  from  what 
has  been  usually  witnessed.  First,  it 
is  important  that  the  resistance  should 
be  distributed  as  near  equally  as  is- 
consistent  with  the  employment  of  the 
vessel,  on  every  line  of  resistance  be- 
low the  line  of  flotation  ;  the  lines  of 
resistance  on  the  after-body  may  be 
filled  out  to  great  advantage  below  the 
surface  of  the  water,  and  by  so  doing, 
we  may  materially  diminish  the  con- 
stant strain  aft  that  exists,  consequent 
upon  the  resistance  on  the  posterior 
part,  wheU  vessels  are  performing  their 


MARINE    AND    NAVAL    ARCHITECTURE. 


71 


evolutions.  We  have  but  to  look  at 
the  white  foam  that  skirts  the  surface 
of  the  contiguous  columns  on  certain 
parts  of  the  line  of  flotation  of  ordinary 
modeled  vessels,  to  learn  from  whence 
conies  this  after-tow ;  by  filling  out  the 
after-body,  we  do  not  mean  that  ir- 
regular shape  so  characteristic  of  Eng- 
lish ships  under  the  old  tonnage  laws, 
taken  from  the  stereotyped  editions  of 
English  works  on  Naval  Architecture  ; 
the  ponderous  buttocks  would  be  re- 
moved^ and  an  equal  bulk  placed  in 
the  part  requiring  augmentation  :  in  a 
word,  the  displacement  would  be  regu- 
lated to  act  in  concert  with  the  resist- 
ance. 

A  very  popular  mode  of  reasoning 
upon  the  subject  of  resistance  is  worthy 
of  notice,  not  on  account  of  its  approx- 
imation to  any  standard  of  truth,  as 
deduced  from  science,  experiments,  or 
daily  practice,  but  on  account  of  its 
predominating  influence  over  the  minds 
of  young  mechanics,  who  are  beginning 
to  think  for  themselves,  and  who  will 
shine  in  the  road  to  science,  when  un- 
shackled from  those  venerated  notions 
so  prevalent  in  the  commercial  world. 
There  is  a  striking  analogy  supposed  to 
exist  between  the  resistance  to  be 
overcome  by  the  ship,  and  that  met 
and  overcome  by  the  fish  ;  hence,  the 
reason  why  many  vessels  are  propelled 
with   the  wrong  end   foremost,  under 


the  false  notion,  that,  because  most  of 
the  various  species  of  fish  are  largest 
near  the  head,  and  have  their  greatest 
transverse  section  forward  of  the  cen- 
tre of  their  length,  it  must  necessarily 
follow,  that  the  ship  must  be  so  con- 
structed, and  when  the  buoyancy  or 
displacement  is  thus  arranged,  the  ves- 
sel is  best  adapted  to  all  the  purposes 
of  commerce.  The  author  can  dis- 
cover no  analogy  existing  between 
the  ship  and  fish  in  their  evolutions 
through  the  trackless  deep.  Were 
this  fallacious  dogma  not  set  at  rest  by 
experiment  in  the  scientific  world,  it 
would  perhaps  be  worthy  of  more  than 
a  passing  glance.  A  body,  partly  im- 
mersed, meets  with  much  more  resist- 
ance than  one  wholly  immersed,  at  a 
corresponding  speed ;  the  body  wholly 
immersed,  displaces  a  volume  of  fluid, 
the  magnitude  of  which  is  precisely 
the  same  as  that  of  the  body  itself, 
while  the  volume  of  fluid  displaced  by 
the  floating  body  is  just  equal  to  the 
entire  weight  of  that  body  ;  and  it  ne- 
cessarily follows,  that  a  body  wholly 
immersed,  meets  with  the  same  amount 
of  resistance  at  every  change  of  posi- 
tion, which  is  not  the  case  with  \essels 
partially  immersed  ;  the  ship  must  con- 
tend with  the  bufferings  of  two  ele- 
ments, while  the  fish  knows  but  one, 
and  that  one  always  tranquil.  But 
another  difficulty,  in  addition  to  many, 


72 


MARINE   AND    NAVAL    ARCHITECTURE. 


presents  itself — the  ship  should  not 
draw  more  than  half  as  much  water 
aft  as  forward,  and  she  should  be  much 
less  buoyant  aft,  so  that  it  will  be 
readily  perceived  the  analogy  does  not 
appear  so  great  after  all — the  fish  pos- 
sessing also  within  itself  the  elements 
of  impulsion.  Under  some  circumstan- 
ces the  ship  meets  with  more  resist- 
ance from  the  wind  than  she  would  if 
wholly  immersed,  and  propelled  at  a 
corresponding  velocity ;  or  the  same 
amount  of  power  applied  upon  a  vessel 
wholly  immersed,  would  produce  an 
equal  amount  of  speed,  apart  from  the 
resistance  of  the  water  which  would 
be  found  to  equal  the  first.  It  is  not 
unfrequently  the  ease,  that  the  power 
of  the  waves  and  wind  is  more  than 
equal  to  all  the  power  of  a  propulsory 
nature  that  can  be  brought  to  bear  on 
a  ship,  while  at  the  same  time  the  re- 
sistance below  the  water  partakes  of 
no  perceptible  change,  or  is  not  in- 
creased. The  resistance  of  the  atmos- 
phere has  seldom  been  brought  into 
the  account  when  summing  up  the 
whole  amount  to  be  overcome,  when  it 
is  remembered,  that  upon  every  square 
inch  of  surface  a  pressure  is  sustained 
of  fifteen  pounds,  and  some  reference 
should  be  had  to  this  part  of  the  resist- 
ance, when  modelling  that  part  of  the 
hull  above  the  greatest  immersed  line 
of  Hotation. 


The  laws  of  propulsion  claim  our 
attention,  and  seem  to  be  almost  in- 
separably connected  with  resistance*  as 
there  can  be  no  propulsion  without  re- 
sistance. The  term,  however,  has  no 
application  to  a  body  moving  on  a 
rigid  plane.  In  its  most  comprehen- 
sive sense,  it  may  be  defined  as  being 
applicable  only  to  such  bodies  as  are 
sustained  on  a  fluid,  for  the  evident 
reason,  that  no  body  sustained  on  a 
rigid  plane  by  the  centre  of  gravity. 
can  be  moved  without  the  application 
of  an  excess  of  power  over  that  con- 
centrated at  the  same.  The  law  of  mo- 
tion, under  such  circumstances,  would 
properly  belong  to  another  branch  of 
mechanics.  When  force  is  applied  to 
a  floating  body,  it  yields  to  the  impulse, 
however  feeble  that  impulsive  power 
may  be  ;  if  it  be  a  continued  pressure 
the  body  must  move  in  the  direction 
of  the  force  applied,  unless  there  be 
some  countervailing  power  acting  at 
the  same  time  in  an  opposite  direction  ; 
and  the  relative  connection  between 
the  moving  body  and  the  impulsive 
power  is  the  speed  attained.  Here, 
again,  we  see  equilibrated  weight  in 
floating  bodies,  standing  out  in  drastic 
contrast  with  equilibrium  in  the  same 
body  when  on  a  rigid  plane.  Resist- 
ance increases  under  the  same  circum- 
stances in  proportion  as  the  density  of 
the  fluidincreases   by  which  the  float- 


MARINE    AND    NAVAL    ARCHITECTURE. 


73 


ing  body  is  sustained  ;  and  were  it  pos- 
sible for  tbe  fluid  on  which  a  ves- 
sel floats  to  become  of  equal  density 
with  the  earth,  and  at  the  same  time 
occupy  no  larger  space  than  when  a 
fluid,  the  vessel,  instead  of  being  sus- 
tained by  a  portion,  being  immersed, 
would  continue  to  rise  until  she  would 
rest  on  the  surface :  under  such  cir- 
cumstances, it  would  require  a  power 
more  than  equal  to  the  weight  of  the 
vessel  to  move  her,  without  the  appli- 
cation of  measures  to  reduce  the  fric- 
tion. In  solid  bodies  floating  on  fluids, 
the  angle  of  surface  in  juxtaposition 
with  the  fluid  itself,  and  area  of  such 
surface,  determine  the  ratio  of  resist- 
ance on  vessels  or  bodies  of  equal 
bulk.  We  have  shown  that  motion 
cannot  be  imparted  to  a  solid  body  in 
equilibrium  floating  on  a  fluid,  without 
the  application  of  external  force  ;  but 
it  does  not  follow  that  the  impulse 
must  be  received  in  the  direction  of 
tbe  motion  thus  imparted,  for  the  evi- 
dent reason,  that  the  effect  produced  is 
at  right  angles  with  the  surface  or 
angle  of  the  plane  receiving  the  im- 
pulse, as  shown  in  Fig.  7 ;  hence,  the 
reason  why  vessels  can  be  impelled 
within  a  few  points  of  tilt  direction  of 
the  wind  ;  and  were  vessels'  sails  so  ar- 
ranged, that  the  right-angled  impulsive 
power  would  be  in  the  direction  of  the 
beam,  the  vessel  could  make  no  head- 


way, hence,  the  reason  why  all  vessels 
have  their  sails  so  arranged,  that  when 
rilled  by  the  wind  (although  braced  up 
to  the  sharpest  point)  the  impulsive 
direction  is  aft  of  the  direction  of  the 
beam.  It  should  be  remembered,  that 
whatever  may  be  the  angle  which 
the  direction  of  the  wind  makes  with 
the  plane  of  the  sails,  the  only  effective 
force  of  the  wind  on  the  sail  is  that 
part  of  the  whole  force  which  can  be 
resolved  into  a  direction  perpendicular 
to  the  surface  of  the  sails ;  therefore, 
whatever  may  be  the  whole  force  of 
the  wind,  its  effective  force  will  vary 
as  the  angle  which  the  direction  of  the 
wind  makes  with  the  sail,  and  as  the 
velocity  of  the  ship  is  in  proportion  to 
the  effective  force  of  the  wind,  it  will 
also  (all  things  else  remaining  un- 
changed) vary  this  angle — see  Fig.  7. 
It  is  evident,  that  when  the  ship  is 
under  sail,  the  direction  of  its  motion 
should  coincide  with  the  direction  of 
the  keel,  inasmuch  as  the  amount  of 
resistance  encountered  on  the  immersed 
part  of  the  hull  is  less  when  the  ship 
moves  in  that  direction  than  it  is  when 
the  line  of  motion  meets  the  ship  ob- 
liquely; all  that  part  of  the  force  of  the 
wind  which  acts  in  any  other  direction 
than  that  of  the  keel,  must  be  a  hin- 
drance to  her  progress,  and  tends  to 
force  her  in  a  direction  in  which  she 
will  meet  with  an  increased  resistance 


10 


74 


MARINE    AM)    NAVAL    ARCHITECTURE. 


from  the  water.  From  what  has  been 
shown,  this  increased  resistance  or  re- 
tarding tendency  must  necessarily  oc- 
cur under  every  circumstance  of  the 
action  of  the  wind  on  the  sails  of  a  ship 
or  other  vessel,  excepting  in  that  under 
which  the  trim  of  the  sail  is  in  the  di- 
rection of  the  beam,  or  at  right-angles 
with  the  keel  of  the  ship.  From  this 
exposition,  the  angle  of  lee-way  de- 
pends wholly  on  the  angle  of  the  sail 
with  the  line  of  the  keel  of  the  vessel, 
without  any  reference  to  the  velocity 
of  the  ship;  and  the  whole  question  of 
equilibrium  existing  between  the  force 
of  the  wind  and  the  resistance  of  the 
water  resolves  itself  into  the  foreyoino 
conclusion,  assuming  the  wind  to  be 
invariable,  and  the  velocity  of  the  ship 
to  remain  unchanged.  But  as  the  va- 
riation in  the  force  of  the  wind  causes 
a  change  in  the  velocity  of  the  ship,  a 
consequent  change  takes  place  in  the 
angle  of  lee-way,  and  no  writer  has 
ever  been  able  to  produce  a  tangible 
theory  upon  this  subject ;  but  the  dis- 
tance a  ship  falls  to  leeward  of  her 
course  in  any  given  time,  may,  witli 
rare  exceptions,  be  easily  ascertained, 
and  tables  formed  from  actual  obser- 
vation for  ships.  In  the  open  sea,  the 
amount  of  lee-way  made  in  a  given 
time,  may  be  measured  by  the  angle 
of  the  ship's  wake,  with  the  line  of  her 
keel  or  a  line  on  deck.     When  a  ship 


is  either   approaching   or  leaving   the 

shore,  and  her  head  is  constantly  kept 
at  the  same  point  of  the  compass,  her 
course  will  be  along  the  line  of  the 
lee-way,  and  by  taking  the  bearing  of 
an  object  on  shore,  we  may,  at  the  ex- 
piration of  a  stated  time,  take  the 
angle  again,  and  the  difference  between 
these  two  angles  will  be  the  angle  of 
lee-way.  But  as  the  pursuit  of  this 
subject  is  less  congenial  to  mechanics 
than  to  nautical  men,  we  will  pursue 
the  legitimate  subject  of  the  article 
under  consideration.  The  centre  of 
propulsion  should  be  located  perpen- 
dicular to  the  centre  of  displacement, 
for  the  evident  reasons,  if  placed  lor 
ward  of  the  centre  of  displacement,  (it 
is  like  a  fulcrum  on  a  precarious  foun- 
dation,) the  bow  yields  to  the  pressure, 
and  the  ship  is  brought  by  the  head  : 
hence,  the  reason  why  so  many  ships 
lose  their  trim  at  sea  when  under  a  press 
of  sail.  The  reasons  almost  universally 
assigned  (when  a  reason  can  be  given 
for  crowding  so  much  sail  forward)  are 
to  prevent  the  ship  from  carrying  too 
much  of  the  weather  helm  ;  in  other 
words,  to  prevent  her  strong  tendenej 
to  come  to  the  wind.  The  laws  of 
leverage  ma™  be  aptly  applied  to  tin 
sails  of  a  ship.  The  centre  of  effort 
of  all  the  sails  (or,  as  the  term  will 
perhaps  be  better  understood,  the 
((Mitre    of  propulsion)    may,    like    the 


«• 


MARINE    AND    NAVAL    ARCHITECTURE. 


75 


fulcrum,  be  concentrated  at  a  single 
point,  and  represented  as  sustaining 
all  the  forces  tending  to  propel  the 
ship  ;  but  like  the  centre  of  gravity, 
it  is  an  imaginary  axis,  and  yet  it  is 
the  index  which  will  faithfully  exhibit 
any  discrepancy  of  moment  in  the  dis- 
tribution of  the  propelling  power. — 
Plate  1  is  designed  to  illustrate  one  of 
the  methods  adopted  in  Europe  among 
men  of  science,  of  locating  the  centre 
of  propulsion  forward  of  the  centre  of 
the  vessel,  longitudinally  divided  on  the 
load-line  of  flotation  ;  the  plate  is  the 
representation  of  a  three-masted  fore 
and  main  topsail  schooner,  with  the 
centre  of  propulsion  3^  feet  forward  of 
the  centre  of  load-line.  Some  Euro- 
pean architects  place  this  point  a  rela- 
tive distance  from  the  centre  of  dis- 
placement, which  is  an  approximation 
to  the  true  method  of  distribution.  It 
will  be  observed,  that  not  only  the 
centre  of  the  area  of  all  the  sail  is  dis- 
tinctly marked,  but  that  the  centre  of 
the  surface  of  every  sail  is  also  marked  ; 
and  by  having  the  centre  and  the 
whole  area  of  all  the  sails  marked  at 
their  respective  places,  we  are  able 
readily  to  determine  an  equivalent  to 
the  whole.  Or,  we  may  adopt  another 
course  to  acquire  the  same  results  : — 
Draw  a  line  that  may  be  regarded  as 
the  mean  base  of  all  the  lower  sails, 
and    another,   that   may  designate   the 


head  of  all  the  lower  sails,  and  continue 
to  do  so  alternately  on  the  foot  and 
head  of  all  the  sails,  the  lines  running 
parallel  to  the  first ;  now  measure  the 
altitude  from  the  head  of  the  royal  to 
the  foot  of  the  lower  sails,  deducting 
the  openings  between  the  lines  repre- 
senting the  head  of  one  sail  and  the  foot 
of  the  next  above;  the  remaining  alti- 
tude divide  into  equal  parts,  and  draw 
ordinates  or  lines  representing  those 
divisions,  setting  down  the  length  of 
those  lines — half  of  the  upper  and  lower 
lines  only  should  be  taken — add  all 
those  lengths  together,  and  divide  by 
the  number  of  parts,  and  you  have  the 
whole  area  of  sail,  the  centre  of  which 
is  the  centre  of  propulsion,  or,  as  is 
sometimes  called,  the  centre  of  effort. 
It  does  not,  however,  follow,  that  any 
number  of  square  feet  above  this  point 
will  effect  the  same  that  an  equal 
,  number  will  below,  either  on  the  velo- 
city or  the  stability  of  the  ship  ;  for  it 
must  be  at  once  apparent,  that  if  the 
laws  of  leverage  are  applicable  to  the 
distribution  of  sail  on  a  ship  or  other 
vessel,  that  the  farther  from  the  ful- 
crum, the  less  the  weight  required  to 
accomplish  the  same  purpose  ;  hence, 
it  is  plain,  that  one  square  foot  of  the 
royal,  the  wind  blowing  with  a  given 
force,  will  not  propel  the  ship  with  an 
equal  velocity  that  the  same  surface 
under  the   same   pressure  would    near 


76 


MARINE    AND    NAVAL    ARCHITECTURE. 


the  hull  of  the  vessel,  for  the  following 
reasons  :  the  power  exerted  on  the  sail 
aloft  has  a  much  greater  tendency  to 
careen  the  vessel,  and  as  a  consequence, 
her  best  sailing  position  is  departed 
from.  The  advantage  of  lofty  sails 
are,  however,  apparent  from  a  know- 
ledge of  the  fact  that  currents  of  wind 
are  often  felt  above,  that  do  not  de- 
scend to  the  surface  of  the  ocean. — 
But,  although  the  same  area  of  sail 
aloft  has  a  much  greater  tendency  to 
heel  the  ship,  yet  it  must  also  be 
borne  in  mind,  that  the  sails  are  much 
smaller  aloft,  and  continue  to  decrease 
in  size  in  proportion  to  their  altitude  ; 
and  this  principle  should  always  govern 
us  in  the  distribution  of  sail,  as  will  be 
shown  more  fully  in  Ghap.  XII.,  on 
masting  and  sparring. 

If  a  ship  were  a  cylindrical  body, 
like  a  tub,  floating  on  its  bottom  or 
flat  side,  and  fitted  with  a  mast, 
and  sail  in  the  centre,  she  would  al- 
ways sail  in  a  direction  perpendicular 
to,  or  at  right-angles  with  the  yard, 
and  as  a  consequence,  would  make  no 
lee-way ;  but,  being  an  oblong  body, 
may  be  compared  to  a  chest,  whose 
length  greatly  exceeds  its  breadth,  and 
being  so  shaped  that  a  moderate  force 
will  propel  her  head  or  stern  foremost, 
while  it  requires  a  very  great  force  to 
propel  her  sideways  with  the  same  ve- 
locity.     The   lee-way  depends   wholly 


upon  the  direction  of  the  impulse,  and 
the  action  of  the  wind  on  the  hull  and 
rigging,  which  augments  the  lee-way. 
Persons  unaccustomed  to  attend  to 
these  things  are  apt  to  imbibe  a  notion 
that  the  velocity  of  a  ship  can  have  no 
sensible  proportion  to  that  of  the  wind. 
"  Swift  as  the  wind"  is  a  proverbial 
expression  ;  yet,  the  velocity  of  a  ship 
always  bears  a  sensible  ratio  to  that  of 
the  wind,  and  even  very  frequently 
exceeds  it.  Fig.  7  exhibits  the  phi- 
losophy of  sailing  by  the  wind.  Many 
have  doubtless  wondered  how  vessels 
could  sail  partly  in  the  direction  from 
which  the  wind  blows.  It  will  be  ob- 
served, by  referring  to  the  diagram, 
that  the  yards  are  braced  as  sharp  as 
they  may  be  to  advantage,  and  that  the 
wind  is  represented  as  blowing  in  the 
direction  of  nearly  one  point  farther 
aft  ;  hence,  it  will  be  quite  apparent, 
that  the  sheet  of  wind  acting  on  the 
sail  is  wedging  the  vessel  along,  and 
that  the  direction  of  the  force  is  shown 
by  the  dotted  line  which  is  at  right-an- 
gles with  the  yard  or  sail :  also,  that 
the  same  line  as  before  stated,  must 
indicate  the  force  as  being  aft  of  the 
beam,  or  the  vessel  can  make  no  head- 
way. Much,  however,  may  be  gained 
by  a  proper  distribution  of  the  surface 
of  sail,  in  order  that  one  part  or  end 
of  the  ship  may  neither  have  more,  nor 
yet  less  than    the    buoyancy  actually 


MARINE    AND    NAVAL    ARCHITECTURE 


77 


requires.  It  is  not  a  little  surprising, 
that  to  the  present  time  nothing  has 
been  done  in  the  United  States  to- 
wards systematizing  the  distribution  of 
the  propelling  power  in  sailing  vessels  ; 
but  each  builder  carves  out  a  path  for 
himself;  and  among  the  many  notions 
that  grow  into  rank  luxuriance  among 
commercial  men,  none  bears  a  more 
glaring  resemblance  to  superstition, 
than  those  pertaining  to  the  propul- 
sion of  vessels ;  hence,  the  reason  of 
so  much  mysticism  ;  each  builder  clings 
to  his  stereotyped  notions  with  a  tena- 
city scarcely  witnessed  in  other  mat- 
ters. It  would  seem,  that  if  experience 
was  the  great  and  grand  palladium  of 
success,  (a  quality  claimed  by  its  adhe- 
rents,) that  it  would  have  done  some- 
thing ere  this,  towards  making  a  reliable 


course,  that  will  regard  the  form  of  the 
vessel  as  an  invariable  index  in  an  ar- 
rangement of  so  much  importance. — 
About  the  time  the  ship's  decks  are 
framed,  the  builder  furnishes  the 
owner  with  a  sketch-draft,  or  the  di- 
mensions of  the  spars  of  the  ship  he  is 
building  for  his  approval ;  by  this 
course,  the  responsibility  is  divided,  the 
builder  relieved,  and  the  vanity  of  the 
owner  flattered.  All  ship-builders  do 
not,  however,  pursue  this  course,  but 
some  have  one  peculiar  to  themselves, 
supposing  they  know  enough  in  rela- 
tion to  the  subject  before  them,  and 
without  consultation,  furnish  the  spar- 
maker  with  a  schedule  of  dimensions. 
We  shall  endeavor,  in  its  appropriate 
place,  to  show  what  is  yet  required  to 
enable  the  ship-builder  to  exclaim — 


Behold  !  the  genius  of  mechanic's  skill 
Ploughs  trackless  furrows  at  her  master's  will, 
As  if  endowed  with  artificial  life, 
To  lash  an  ocean  into  angry  strife  ! 


78 


MARINE  AND    NAVAL    ARCHITECTURE. 


CHAPTER    III. 

Importance  of  a  Knowledge  of  the  location  of  the  Centre  of  Effort — Method  of  obtaining  it — The  Model,  an 
American  Invention — Its  Advantages — Its  Origin — Its  complete  Adaptation  to  our  Wants — Instructions 
for  making  them. 


In  this,  as  in  the  former  chapter,  it 
will  be  found  that  a  judicious  union  of 
theory  and  practice  is  necessary  to 
carry  the  branches  of  which  it  treats 
onward  towards  perfection ;  the  two 
must  be  united — cordially  and  harmo- 
niously united;  practice  must  not  de- 
cline the  assistance  of  theory,  nor  must 
theory  disdain  to  be  taught  the  lessons 
of  practice.  "  There  are  many  princi- 
ples," says  Mr.  Atwood,  (a  distinguished 
writer  upon  this  science,)  "  deducible 
from  the  laws  of  mechanics,  which  it 
is  probable  no  species  of  experiment, 
or  series  of  observations,  however  long 
continued,  would  discover ;  and  there 
are  others  no  less  important,  which 
have  been  practically  determined  with 
sufficient  exactness — the  investigation 
of  which  it  is  scarcely  possible  to  infer 
from  the  laws  of  motion — the  compli- 
cated and  ill-defined  nature  of  the  con- 
ditions, in  particular  instances,  render- 
ing analytical  operations  founded  on 
them  liable  to  uncertainty."  It  is 
true,  indeed,  as  the  same  writer  re- 
marks in  another  place,  that,  although 


all  results  deduced  by  strict  geometri- 
cal inference  from  the  laws  of  motion 
are  found  by  actual  experience  to  be 
perfectly  consistent  with  matter  of  fact, 
when  subjected  to  the  most  decisive 
trials,  yet,  in  the  application  of  these 
laws  to  the  subject  in  question,  diffi- 
culties often  occur,  either  from  the 
obscure  nature  of  the  conditions,  or 
the  intricate  analytical  operations  aris- 
ing from  them,  which  either  renders  it 
impracticable  to  obtain  a  solution,  or 
if  a  result  is  obtained,  it  is  expressed 
in  terms  so  involved  and  complicated, 
as  to  become  in  a  manner  useless  to 
any  purpose.  Thus,  the  mathemati- 
cian has  thrown  barriers  in  the  path 
to  knowledge  on  this  science ;  bent  on 
his  purpose,  he  gives  a  solution  to  a 
problem,  while  \ie  is  perfectly  indiffer- 
ent whether  the  world  can  or  cannot 
comprehend  the  same.  And  it  is  re- 
markable, in  how  many  instances  un- 
educated men  have  anticipated  the 
soundest  deductions  of  the  most  en- 
larged  theories,  particularly  in  the  Uni- 
ted States;  so" much  so,  that  they  have 


MARINE    AND    NAVAL    ARCHITECTURE, 


79 


become  proverbial.  It  is  one  of  the 
instinctives  of  Genius  to  mark  out  an 
independent  course  of  action.  The 
untutored  savage,  though  a  stranger  to 
Newton's  third  law  of  motion,  applies 
it  to  practical  use,  when  he  sets  his 
canoe  afloat  by  pushing  with  a  pole 
against  the  shore,  or  by  adding  a  mo- 
mentum to  his  missile  weapons,  by 
gaining  an  eminence.  The  practical 
knowledge  the  builder  of  a  canoe  exer- 
cises, is  obtruded  on  the  organs  of  ex- 
ternal sense  by  the  hand  of  nature 
herself.  The  Indian  found,  for  ex- 
ample, that  a  particular  disposition  of 
the  sail  of  his  little  bark  would  give  it 
greater  velocity  than  any  other ;  a 
change  of  position  of  his  own  body,  or 
of  a  stone  in  the  bottom  of  his  canoe, 
would  alike  influence  its  sailing  quali- 
ties. These  to  him  would  be  maxims 
of  great  practical  value ;  for,  by  the 
operation  of  this  instinctive  genius  two 
objects  were  accomplished  by  the  same 
movement;  for, while  he  made  abetter 
distribution  of  the  buoyancy,  he  also 
augmented  the  stability,  and  as  a  con- 
sequence increased  the  speed.  Thus 
we  perceive,  that  without  the  aid  of 
science,  man  may  be  brought  to  the 
recognition  of  its  fundamental  laws,  or 
to  the  discovery  of  this  most  important 
truth,  viz.,  that  stability  is  an  all-import- 
ant qualification. 

The  importance  of  natural  stability 


will  be  recognised  when  it  is  remem- 
bered that  artificial  stability  cannot 
compensate  its  loss.  But  while  many 
assent  to  the  dogma,  few  indeed  have 
given  the  subject  that  attention  its  im- 
portance demands.  Ship-builders  in 
the  United  States  have  had  recourse 
to  analogy  for  determining  the  propor- 
tions of  this  important  property,  which 
perhaps  in  ordinary  cases  may  answer 
every  purpose;  but  cases  have  occurred 
in  which  our  most  prominent  builders 
have  been  left  entirely  in  the  dark  upon 
this  subject  :  hence  the  necessity  of 
a  rule  of  reference  upon  a  subject  of 
such  vast  importance.  To  illustrate 
the  principles  upon  which  the  stability 
of  equilibrium  depends,  it  will  be  ne- 
cessary to  assume  certain  conditions 
from  which  we  may  be  able  to  deduce 
tangible  results.  If  a  ship  has  been 
brought  by  any  force  out  of  her  erect 
position,  it  is  important  that  the  cir- 
cumstances be  indicated  by  which  she 
will  again  adopt  it ;  this  ability  is  very 
properly  called  stability,  and  the  amount 
of  effort  exerted  for  the  recovery  of  the 
erect  position  is  the  index  showing  the 
value  of,  or  the  amount  of  stability,  and 
as  a  consequence,  the  greater  efforts 
to  maintain  the  erect  position,  the 
greater  the  stability  of  the  vessel.  It 
must  be  quite  apparent  to  the  most 
casual  observer,  that  an  addition  to  the 
breadth  of  a  vessel  adds  to  the  stability. 


80 


MARINE  AND  NAVAL  ARCHITECTURE. 


But  how  much  has  been  added  to  the 
stability  by  increasing  the  breadth  one 
inch  or  one  foot,  are  questions  that 
the  most  experienced  cannot  answer 
from  experience  alone ;  he  must  have 
recourse  to  mathematical  expositions, 
which  furnish  the  basis  of  every  intel- 
lectual art  in  the  catalogue.  It  must  be 
remembered  that  the  whole  theory  of 
stability  is  embodied  in  the  emergence 
and  emersion  of  that  part  of  the  ves- 
sel in  the  immediate  vicinity  of  the  line 
of  flotation — in  other  words,  the  vessel 
being  careened,  a  portion  of  one  side  is 
immersed,  while  the  opposite  side  is 
emerged ;  consequently,  the  power  or 
effort  exerted  by  the  immersed  side  to 
push  the  vessel  upright,  and  the  lever- 
age of  the  opposite  side  to  pull  down- 
ward the  index,  showing  that  power  is 
increased  or  diminished  by  adding  to  or 
detracting  from  the  breadth  of  the  ves- 
sel, or  by  adding  to  or  taking  from  the 
depth,  and  is  all  that  is  expressed  in 
the  solution  of  the  problem  of  stability. 
We  shall  endeavor  to  give  a  clear  and 
luminous  exposition  of  this  subject  in 
all  its  bearings  ;  and  if  the  reader  will 
follow  us  attentively,  we  think  he  can- 
not fail  to  understand  this  subject, 
which  has  perplexed  mechanics  in 
every  age,  and  which  may,  with  truth, 
be  regarded  as  one  of  the  most  diffi- 
cult problems  in  the  science  of  building 
ships. 


Suppose  A.  D.  B.,  Fig.  8,  to  be  the 
greatest  transverse  section  or  dead-flat 
frame  of  a  vessel  in  the  position  of  its 
stability ;  draw  a  vertical  line  through 
the  centre  of  gravity  of  the  section, 
and  it  will  be  found  that  in  this  line 
the  centre  of  displacement  or  the  centre 
of  gravity  of  displacement  is  located, 
either  above  or  below  E.,  which  repre- 
sents the  centre  of  gravity.  Careen  the 
vessel  as  in  Fig.  9,  and  let  F.  be  the 
centre  of  displacement ;  draw  a  vertical 
line  from  F.  until  it  intersects  the  mid- 
dle line  D.  C.  at  G.,  above  the  centre 
of  absolute  gravity  E.,  at  which  point 
the  whole  weight  of  the  vessel  is  con- 
centrated, and  as  a  consequence,  the 
value  of  E.  is  the  entire  weight  of  the 
vessel.  Before  proceeding  farther,  we 
will  examine  the  peculiar  properties  of 
M.,  which  is  found  to  be  the  point 
where  the  two  lines  of  flotation  cross 
each  other,  viz.,,  the  upright  and  the 
careened  lines,  and  as  a  consequence, 
the  efforts  of  the  water  to  right  the  ves- 
sel are  centered  at  F.,  in  a  vertical  line 
from  M.,  and  operate  at  G.  when  the 
vessel  is  drawn  aside  from  her  erect 
position.  E.  works  downwards  in  a 
vertical  line,  as  from  E.  to  L.,  and 
the  pushing  powers  upwards ;  con- 
sequently these  forces  turn  the  body  or 
incline  the  ship  to  right,  when  the 
power  that  careened  her  is  removed, 
and  she  floats  with  stability.     But  if 


■ 


MARINE    AND    NAVAL    ARCHITECTURE. 


81 


the  centre  of  gravity  of  the  displaced 
water  be  at  H,  and  the  vertical  H  J 
meets  G  D  between  E  and  D,  as  in  Fig-. 
9,  then  the  pressure  of  the  water  acts 
upwards  in  the  direction  H  J,  and  the 
weight  of  the  body  downwards  in  the 
direction  E  L ;  these  forces  will  there- 
fore have  a  tendency  to  turn  the  body 
still  farther  from  its  former  position, 
and  it  floats  without  stability  :  this  will 
be  a  state  of  instantaneous  equilibrium. 

Through  F  the  centre  of  gravity  of 
the  displaced  fluid,  draw  the  vertical 
line  F  M  G  intersecting  C  D  in  G  ;  the 
point  G  is  called  the  meta-centre,  or  as 
we  have  denominated  it,  the  centre  of 
effort ;  it  is  evident  from  what  precedes, 
that  the  equilibrium  will  be  stable  when 
G  is  above  E,  and  instantaneous  when 
it  is  below  E. 

To  determine  the  centre  of  effort,  let 
S  (Fig.  10)  be  the  centre  of  gravity  of 
the  body,  E  that  of  the  displacement  in 
the  erect  position  of  the  vessel,  and  F 
in  its  inclined  position,  h,  ti  and  R  the 
centres  of  gravity  of  N  L  B,  A  L  M  and 
BLMC  respectively.  If  through  the 
point  E  we  draw  a  vertical  plane  at 
right  ancles  to  the  section  N  C  A,  and 
take  the  moments  with  reference  to  this 
plane,  we  have,  if  we  represent  the  per- 
pendiculars from  h'  and  h  upon  E  J  by 
p  and  q. 

MCNx  E  H  =  MC  B  L  x  RT  +  LBX  Xj(l) 
A  C  B  x  o  =  M  C  B  L  x  KT-ALM  x  q  (2) 


From  (2)  M  C  B  L  X  R  T  =  A  L  M  X  q  (3) 

But  A  L  M  =  L  B  N  (4) 

Substituting  (3)  and  (4)  in  (1) 

M  C  N  x  E  H  =  L  B  N  x  h  (5) 

making  j>  +  q  =  h 


Whence         E  H  =  ""'J**!?  x  h 

"'•MCN 


(6) 


If  the  distance  ES=i,  and  the  an- 
gle H  P  E  =  cp 

S  G  =  E  H  —  d  sin  ? 

TOl-  N  L  B 

=     — X  h  —  cl  sin  <f>       (7) 

voi.MCN  V  / 

Designating  the  weight  of  the  vessel 
by  m,  the  moment  of  stability  will  be 

N  L  B  . 

(8) 


971 


( 


—  h  —  d  sin  is 
MCN      + 


) 


The  upper  sign  is  to  be  used  when 
S  is  above  E,  and  the  lower  sign  in  the 
contrary  case, 

£p=      EJI=NLBilA 

sin  <p        MCN    sin? 

the  distance  from  the  centre  of  displace- 
ment to  the  centre  of  effort. 

We  will  now  determine  the  analyti- 
cal values  of  E  H,  E  P,  &c.  If  we 
suppose  the  floating  body  to  be  a  little 
inclined,  the  plane  of  flotation  AB  is  re- 
placed by  P  N  ;  these  two  planes  cut 
by  a  vertical  plane,  give?  the  section 
N  L  B  :  if  we  continue  to  draw  parallel 
vertical  planes,  we  shall  divide  the  solid 
into  an  infinite  number  of  elementary 
solids  parallel  to  N  L  B. 

If  we  take  the  common  intersection 


it 


82 


MARINE    AND    NAVAL    ARCHITECTURE. 


of  the  two  planes  N  L  M  and  B  L  A  for 
the  axis  of  x,  and  place  the  axis  of  y 
perpendicular  to  that  of  x,  in  the  plane 
N  L,  tlie  ordinates  will  be  the  perpen- 
diculars N  L,  N'  L ,  N"  L",  &c.  If  the 
angle  cp  lie  infinitely  small,  AL  =  LB, 
therefore 

P  =  q  =t  y  and  h  =  p  +  q  =  I  y 

The  area  of  the  section  BDN  is 

&  sin  <f>.  y"  =  h.  <f>  y~  (10) 

Multiplying  this  section  by  dx,  we  shall 
have  for  the  contents  of  the  elementary 
solid  BDN,h 

£  <p  y"  d  x 

and  for  its  moment, 

£  <P  y-  d  x  x  §  y  =  J  <p  y3  d  x 

Hence 

(11)  l  vf'f~  d  Jo  =  sum  of  the  elementary  solids. 

(12)  iffy3  dx=  sum  of  the  moments  of  the 

elementary  solids. 

If  we  substitute  these  values  in  equa- 
tions, (6,)  (7,)  (8)  and  (9,)  and  represent 
the  volume  of  the  displacement  by  V, 
we  have 

§  sin  <p  J*  y3  dx 


EH: 


SG 


§  sin  <p  y*  if  d  x 


EP 


J  f  V 


V 

3  dx 


V 


Moment 
stab 


;£/  — ( 


§  sin  <?>  y* 


(13) 

—  <Z  sin  <p        (14) 

(15) 

—  d  sin  <p   J  (16) 


If  we  suppose  d  x  to  be  finite,  and 
that  the  vertical  planes  parallel  to  ACN 
are  equidistant  from  each  other — the 
ordinates  being  yx,  y„,  y3,  &c, 


EH 


3  3  3 

_|-sin  <P  (yi  +  lh  +  2/3+- 


.)</.r     %s\n<p^yidx 


C     3  3 

E  P  =%\yi  +  y-2  + 

V 


..} 


rfa; 


5  >/,  d  .T 


Moment  of 
stability 


m 


Q 


sin  <p  §  yi  d  x 


—  rf  sin  <p   j 


Hence,  to  calculate  the  moment  of 
stability,  we  must  know  the  distance 
from  the  centre  of  gravity  of  the  vessel 
to  that  of  the  displacement ;  as  it  is 
inconvenient  in  most  cases  to  deter- 
mine the  centre  of  gravity  of  the  ship, 
the  usual  method  in  comparing  the 
stability  of  different  ships  is,  to  suppose 
that  the  two  centres  coincide. 

The  calculation  of  Si  y\  dx  is  to  be 
performed  in  the  same  manner  as  in 
calculating  the  area  of  a  plane  figure, 
the  cubes  of  the  ordinates  being  used 
instead  of  the  ordinates. 

In  the  division  of  the  ordinates  in  the 
upper  water-line,  there  remain  the  two 
triangles  r  a  a  and  id  h  h',  which  must 
be  included  in  the  calculation. 

For  such  a  triangle  l  y\  dx  is  equal 
to  the  cube  of  the  base  of  the  triangle 
(Fig.  13)  multiplied  by  one-fourth  of  its 
height ;  for,  if  a  be  the  base  of  the  tri- 
angle, and  b  the  height,  then  a  =  \  b, 
and  the  middle  ordinate  is  =  \  a. 


MARINE  AND  NAVAL  ARCHITECTURE. 


83 


Cubes. 

a 

3 

a 

1 

3 

a 

I  a 

1        3 
8« 

4 

\d 

0 

0 

1 

0 

Sum—%  a? 
hd  =  ±b 


|a3Xli  =  la3J, 


The  following  is  the  formula  for  cal- 
culating the  distance  to  the  centre  of 
effort  from  the  centre  of  displacement : 


Ordinates 

Cubes 

of  thrt  npper 

of  the 

\raur-line. 

Oriliuates. 

3 

3 

!/i 

2/i      . 

1 

l2/i 

3 

3 

!/2 

2/2 

4 

4  2/2 

3 

3 

2/3 

2/3 

2 

2  2/3 

3 

3 

y* 

2/4 

4 

4  J/4 

3 

3 

2/5 

2/5 

2 

2  2/5 

3 

3 

2/o 

2/6 

4 

*  2/6 

3 

3 

2/7 

2/i 

1 

lyr 

s 

Making, 

J/l  +  J/2  +  3/3  +  2/4  +  2/5  +  J/6  +  y-t  =  S 

J  distance  between  the  sections  =&dx. 

S  X  §  dx=  %S.  dx 

Therefore 

3  

£  7/i  d  x  —  J  S.  d  x  +  |  w  h  X  A  A'  X  *ra  X  a  a'—  S' 

Consequently 

2  yi<Za;        s_' 

A     ~~     V 


8 


for  the  height  V  of  the  centre  of  effort 
above  the  centre  of  gravity  of  the  dis- 
placed fluid. 


The  moment 
of  stability 


=  m  (  §  —  —  d  )  sin  ? 


It  is  our  province  not  only  to  deli- 
neate theory,  but  to  show  to  what  ex- 
tent it  accords  with  practice,  and  to 
make  a  sirmark  where  they  agree. 

In  the  theory  of  stability  it  is  assu- 
med, that  the  centre  of  displacement  is 
the  oscillating  point, — that  is  true  only 
at  small  inclinations, — the  surface  of 
the  water,  under  some  circumstances, 
becomes  the  fulcrum  ;  this  discrepancy 
however  does  not  affect  the  solution  of 
this  great  problem.  In  the  resolution 
of  forces  operating  on  a  floating  body 
that  is  not  homogeneous,  the  influence 
of  every  force  is  increased  or  diminished 
at  every  change  in  the  form  of  the  line 
of  flotation.  The  construction  and  pro- 
perties of  the  curve  that  marks  the  path 
of  the  centre  of  effort,  is  a  subject  of 
geometrical  reasoning,  and  considered 
as  such,  is  liable  to  neither  ambiguity 
nor  error  ;  but  on  what  grounds  these 
properties  are  applied  to  measure  the 
stability  of  vessels,  or  to  estimate  their 
security  from  upsetting  when  much  in- 
clined, has  never  been  fully  explained. 
Having  already  enlarged  upon  the  the- 
ory, it  may  suffice  to  add,  that  when 
the  ship's  inclination  has  brought  the 
middle  line  (which  passes  through  the 
centre  of  the  keel,  stem  and  stern-post) 
parallel  to  the  surface  of  the  water,  the 
centre  of  the  absolute  gravity  again  as- 
serts its  prerogative,  and  when  brought 
vertically  in  line  with  the  centre  of  dis- 


S4 


MARINE    AND    NAVAL    ARCHITECTURE, 


placement,  the  ship  is  just  as  likely  to 
upset  as  to  come  back ;  in  a  ship  of 
proportionate  dimensions  the  centre  of 
gravity  is  low,  and,  (when  properly 
shaped,)  the  centre  of  buoyancy  high  ; 
the  ship  would  then  return  to  the 
erect  position,  even  though  the  keel 
were  above  the  surface  of  the  water, 
when  the  force  that  careened  her  was 
removed.  It  is  only  those  ill-shaped 
disproportionate  ships  that  are  thrown 
down  on  their  beam  ends  ;  it  is  possible 
that  any  ship  may  be  thus  stricken 
down,  but  in  nine  cases  out  of  ten  they 
are  such  ships  as  have  a  high  centre  of 
absolute  gravity,  and  a  low  centre  of 
displacement.  In  looking  into  this 
important  part  of  the  science  of  ship- 
building, the  mechanic  will  receive  an 
additional  stock  of  information  by  cut- 
ting a  piece  of  pasteboard  to  the  shape 
of  the  greatest  transverse  section,  mark- 
ing the  lines  of  flotation,  the  centre  of 
gravity  and  the  centre  of  displacement 
as  taken  from  the  calculations  ;  he  will 
then  discover  the  mannerinwhieh  these 
forces  perform  their  evolutions  around 
the  centre  of  motion  ;  a  pin  or  needle 
may  represent  the  axis.  It  should  be  re- 
membered that  the  area  of  the  immersed 
surface  or  the  solid  of  immersion  must  be 
invariable,  notwithstanding  the  line  of 
flotation  is  changing  at  every  change 
in  the  inclination.  It  must  also  be  re- 
membered that  as  soon  as  the  centre 


of  gravity  emerges  by  the  inclination  of 
the  ship,  the  centre  of  displacement 
becomes  the  oscillating  point,  and  the 
distance  between  the  centre  of  dis- 
placement and  the  centre  of  gravity  will 
determine  how  much  farther  the  ship 
will  go  without  being  able  to  return  to 
the  upright  position.  The  centre  of 
effort  should  not  be  less  than  eight  feel 
above  the  centre  of  displacement,  in 
order  that  the  ship  may  have  a  sufli 
ciency  of  stability  for  sea  voyages. 
This  applies  to  ships  of  from  eight  hun- 
dred to  one  thousand  tons  burthen. 
There  can  be  no  invariable  rule  given 
that  will  apply  to  all  sizes  and  descrip- 
tions of  vessels.  The  centre  of  dis- 
placement, however,  will  regulate  the. 
centre  of  effort,  and  is  an  index  that 
will  exhibit  any  discrepancy  of  magni- 
tude in  the  ship's  proportionate  dimen- 
sions. In  the  United  States  the  proper 
location  of  the  centre  of  this  particular 
force  is  seldom  if  ever  thought  of,  while 
in  different  parts  of  Europe  among  men 
of  science  it  is  seldom  forgotten,  and  is 
found  within  certain  prescribed  limits, 
which  multiplied  by  the  height  of  the 
load-line  above  the  base,  will  furnish  a 
medium  as  well  as  the  extremes  beyond 
which  it  should  not  be  placed  vertically  ; 
its  longitudinal  limits  are  equally  well 
defined.  The  vertical  maximum  dis- 
tance below  the  load-line  is,  .4  x  by 
the  height  or  multiplied  by  II;   the  mi- 


MARINE  AND    NAVAL    ARCHITECTURE. 


85 


iiiiiiLim  distance  below  the  load-line  is 
.3215  x  by  H,  and  the  medium  distance 
below  the  load-line  is  .3623  x  by  H. 
For  example,  we  assume  the  load-line 
of  a  ship  to  be  fourteen  feet  above  the 
base-line,  we  have  then 


Feet. 

Maximum. 

Feet. 

H=  14 

X     .4    = 

5.  6 

Medium. 

Feet. 

H  =  14 

X  .3623  = 

5.0722 

Minimum. 

Feet. 

H  =  14  X  .3215  =  4.5010 

The  horizontal  maximum,  medium  and 
minimum  distances  for  the  centre  of 
displacement  forward  of  the  centre  of 
load-line,  may  be  found  in  the  same 
maimer.  Let  L  represent  the  length 
of  the  load-line  between  the  rabbets, 
and  assuming  the  length  to  be  150 
feet,  we  have 


Feet.  Maximum.         Feet 

L  =  150  x  .052  =  7.  S 
forward  of  the  middle  of  the  load-line. 
This,  it  will  be  observed,  is  the  forward 
extreme. 
Again,  let 


Feet. 


Feet. 


150  x  .0175  =  2.G25 


forward  of  the  middle  for  the  medium, 
and  for  the  after  extreme  we  have 


Feet.        Minimum.       Feet. 


L  =  150  X  .01  =  1.  5 

forward  of  the  middle  of  the  load- 
line  for  the  centre  of  displacement.  It 
will  be  perceived  by  this  hypothesis, 
that  vessels  with  their  centres  of  dis- 
placement thus  arranged,  would  draw 
more  water  aft  than  forward,  (provided 


their  keels  were  of  parallel  depth  ;)  a 
practice  that  has  no  basis  in  the  prin- 
ciples   of    philosophy    or    experience. 

The  minimum  distance,  however, 
contemplates  a  parallel  draft,  or  very 
nearly  so.  In  modelling  vessels  with- 
out the  draught,  a  knowledge  of  the 
location  of  those  points  is  dispensed 
with,  but  not  without  hazarding  more 
than  any  other  than  American  ship- 
builders would  be  willing  to.  We  shall 
now  endeavor  to  give  an  example  of 
the  maimer  of  arranging  the  tables  of 
displacement  and  its  connections,  with 
other  important  points  to  be  determ- 
ined, in  the  calculations  on  the  Ocean 
Steamer,  Plate  2,  and  in  doing  this  we 
shall  adopt  in  practice  that  which  we 
have  endeavored  to  define  in  theory. 
There  are  several  methods  of  calcu- 
lating the  displacement,  but  we  shall 
adopt  the  parabolic  system  as  being  the 
most  efficient  that  has  yet  been  used, 
and  adapting  itself  to  the  wants  of 
Marine  Architects,  calculations  by  this 
system  are  very  generally  adopted  by 
men  of  science  in  Europe,  but  their 
utility,  with  rare  exceptions,  has  never 
been  tested  in  the  New  World. 

This  system  of  calculating  areas 
was  first  applied  to  the  displacement 
of  floating  bodies  by  Chapman,  the 
justly  celebrated  Swedish  Naval  Archi- 
tect. In  the  annexed  tables  each  water- 
line  has  a  separate  column  of  calcula- 


SG  MARINE    AND    NAY 

tions,  while  the  same  line  contains  the 
same  results  in  all  the  columns  of  the 
first  division,  or  as  tar  as  the  first  num- 
bers of  reference  extend.  The  first 
twenty  lines  contain  the  half-breadths 
of  the  frames  or  sections  from  the  mid- 
dle line  to  the  several  water-lines  on 
which  they  are  taken;  and  on  their  re- 
spective frames,  the  rule  under  this 
system  requires  alternate  multipliers, 
the  products  of  which  are  added  toge- 
ther as  on  the  twenty-first  line,  this  sum 
is  divided  by  three,  and  the  quotient  mul- 
tiplied by  ten,  because  the  sections  or 
fourth  frames  are  ten  feet  apart.  The 
last  product  is,  as  will  be  seen  on  the 
twenty-fourth  line,  the  half  area  of  the 
line  on  which  it  is  taken  aft  of  frame 
p.  The  vertical  line  of  figures  on  the 
rieht  of  each  water-line  column  are  the 
products  obtained  by  multiplying  the 
number  of  the  sections  from  frame  40, 
by  the  last  product,  and  from  which  is 
obtained  half  the  horizontal  moments. 
The  moment  (whether  horizontal  or 
vertical)  is  the  quantity  multiplied  by 
the  distance  of  its  centre  of  gravity 
from  a  fixed  plane.  Now,  the  fixed 
plane  is  section  40 ;  the  quantity  is 
found  in  the  products  of  the  half 
breadths  multiplied  by  the  rule  of  alter- 
nate multipliers.  The  sum  of  the  last 
column  divided  by  three,  and  the  quo- 
tient multiplied  by  the  square  of  the 
section    distance,    which    is    ten    feet, 


AL    ARCHITECTURE. 

equals  one  hundred;  this  last  product 
is  half  of  the  horizontal  moments  from 
section  40  to  frame  p.  In  the  right- 
hand  column  of  the  fortieth  line  of  each 
water-line  calculation,  we  have  the  half 
horizontal  moments  of  the  part  forward 
of  p,  obtained,  as  will  be  seen  by  refer- 
ing  to  the  table  in  the  same  manner; 
this  sum  must  be  added  to  the  amount 
aft  of  p.  The  half  area  of  the  water- 
line,  to  which  the  calculation  belongs, 
is  divided  into  the  sum  total  of  the 
horizontal  moments,  and  the  quotient 
furnishes  the  distance  (in  feet  and  deci- 
mal parts  as  explained  on  page  3)  from 
section  40  to  the  centre  of  displace- 
ment of  the  same,  (or  the  centre  of 
gravity.)  In  order  to  obtain  the  centre 
of  gravity  of  the  keel  we  may  proceed 
as  follows:  Length  of  keel,  straight- 
rabbet,  213  feet,  half  area  between  rab- 
bets siding  direction  or  transversely  .5, 
then  we  have  this  formula, 

Length.         Breadth.     Square  feet. 

213    X    .5  =  106.5 

the  half  area.  It  then  follows  that  the 
centre  of  gravity  is  106.3  feet  distant 
from  section  40.  Therefore,  106.5  x 
106.3  =  11310.3  the  half  horizontal 
moments  of  the  keel.  The  next  cal- 
culation we  shall  endeavor  to  explain, 
will  be  that  of  obtaining  the  centre  of 
the  entire  displacement  from  the  half 
area  of  the  water-lines,  and  their  hori- 
zontal moments,  as  found  in  the  middle 


MARINE  AND  NAVAL  ARCHITECTURE. 


g    # 


cqIuiiius  of  the  lower  section  of  the 
tables,  it  will  be  seen  that  the  rule  of 
alternate  multipliers  is  also  used  here, 
and  the  same  course  is  pursued  as  in 
the  upper  columns.  It  will  also  be  ob- 
served, that  the  calculations  of  the 
water-lines  furnish  only  the  half  areas 
of  the  same,  but  from  the  lower  sec- 
tion of  the  tables  we  obtain  the  entire 
displacement  by  adding  those  half  areas 
into  one  sum,  then  multiplying  by  the 
alternate  numbers  and  dividing  the  sum 
total  of  their  product  by  three,  the  quo- 
tient being  multiplied  by  the  distance 
between  the  lines,  which  is  1.5  feet, 
gives  half  of  the  entire  displacement, 
which  divided  into  the  vertical  moments 
furnishes  the  altitude  of  the  centre  of 
gravity,  or  its  distance  below  the  sixth 
water-line.  We  next  obtain  the  centre 
of  the  entire  displacement  longitudinal- 
ly from  the  half  areas  and  their  cubes 
as  shown  in  the  lower  section  of  the 
tables.  The  calculation  for  the  centre 
of  effort  will  be  found  on  the  right  of  the 
lower  section  of  the  tables.  The  prob- 
lem of  determining  the  location  of  this 
important  point,  we  have  endeavored 
to  solve  in  all  its  bearings  or  relations  ; 
its  altitude,  like  the  length  of  a  lever, 
determines  the  power  with  a  given 
weight;  and  although  to  give  the  theory 
of  the  centre  of  effort,  we  are  com- 
pelled to  resort  to  the  higher  branches 
of  mathematics,  yet  in  its  practical  re- 


sults we  have,  we  think,  made  it  per- 
fectly intelligible  to  an  ordinary  mind. 
The  half-breadths  of  the  sections  are 
taken  on  the  load-line,  beginning  with 
section  40  as  when  obtaining  the  half 
area,  and  taking  all  the  sections  on  the 
same  line  on  which  the  half-breadth  is 
shown;  its  cube  is  also  shown,  or  the 
number  multiplied  by  itself  and  the  pro- 
duct by  the  same  a  second  time,  for 
example,  1728  is  the  cube  of  12,  thus 
12  x  12  =  144  x  12  =  172S,  so  with  the 
half-breadths,  in  calculating  the  centre 
of  effort.  It  must  be  observed  in 
adopting  the  parabolic  system  not  only 
for  the  ends  of  the  vessel,  but  in  calcu- 
lating the  displacement  and  eentre  of 
effort,  that  the  water-lines,  with  the 
base-line  and  the  number  of  ordinates, 
sections  or  frames,  must  be  odd,  so  that 
the  first  and  the  last  sections  have  the 
same  multipliers;  likewise  in  obtaining 
the  altitude  of  the  centre  of  displace- 
ment, it  is  important  that  there  should 
be  an  even  number  of  water-lines, 
which  with  the  keel,  will  make  the 
number  odd.  The  general  rule  for 
finding  the  contents  of  surfaces  and  so- 
lids by  the  equidistant  ordinate  method, 
is  included  in  this  proposition,  viz. :  If 
any  right  line  as  r  10  Fig.  13  be  divi- 
ded into  an  even  number  of  equal  parts 
(which  as  a  consequence  makes  an 
odd  number  of  lines)  ly  "if,  &c,  and  at 
the  points  of  division  be  erected  per- 


M  AIM  \  I :    A  N  D    X  AVAL    ARCH1  T  E  CTDRE, 


S8 
# 

pendicular  ordinates,  such  as  a  a,  h  h, 
and  so  on,  terminated  by  any  curve, 
such  as  Fig.  13,  or  any  other  form, 
then  if  a  be  put  for  the  sum  of  the 
first  and  last  ordinate  a  a,  h  h,  B  for 
the  ordinate  marked  "~y4y6y,  &c,  and 
C  for  the  sum  of  3y  zy,  &c,  viz.,  the 
third,  fifth,  and  so  on,  or  the  odd  ordi- 
nates,  excepting  the  first  and  last ;  then 
the  common  distance  \j  2y,  &c.  of  the 
ordinates  being  multiplied  into  the  sum 
arising  from  the  addition  of  a,  four 
times  2y  and  twice  \j,  &c,  one-third 
of  the  product  will  be  the  area  a  a,  h  h 
very  nearly.      That  is, 

a  +  4  -ij  +  *y 
3 

D  =  area,  D  being  =  to  a  "y  *y,  &c. 
The  same  theorem  will  serve  equally 
well  for  the  contents  of  other  surfaces, 
by  using  the  section  perpendicular  to 
the  axis  or  middle  line,  and  is  an  ex- 
cellent approximation  for  the  area  of  all 
solids.  The  greater  number  of  ordi- 
nales  (or  frames  if  you  please)  that  are 
taken,  the  more  accurately  will  the 
area  or  capacity  be  determined,  as  it 
will  work  equally  as  well  on  the  inside 
of  the  vessel  as  the  outside,  and  is  some- 
times used  in  cask  ffauffinff.  The  rea- 
son  why  the  calculations  in  the  tables 
do  not  extend  to  the  forward  perpen- 
dicular, and  dispense  with  the  calcula- 
tions of  a  triangular  part,  is  found  in 
this  fact;  the   several    lines   below   the 


load-line  arc  shorter,  and  being  of  dif- 
ferent lengths  would  require  a  perpen- 
dicular for  each  line,  and  as  a  conse- 
quence, the  ordinates  would  require  a 
corresponding  change ;  it  may  be  well 
to  observe  that  section  40  was  taken 
somewhat  larger  than  the  half  breadth 
would  require,  in  order  that  no  calcu- 
lation would  be  required  aft  of  the  per- 
pendicular. It  should  be  remembered, 
that  the  perpendicular  is  at  the  inside 
of  the  rabbet,  on  the  load-line  of  flota- 
tion, and  we  feel  safe  in  marking  the 
terminations  of  this  line  as  the  only 
proper  place  for  the  perpendiculars  of 
any  vessel.  We  are  aware  that  the  per- 
pendicular has  been  located  higher  than 
the  load-line  by  naval  architects,  but  the 
author  is  unable  to  discover  any  good 
reason  for  adhering  to  a  practice  that 
has  not  shown  itself  to  have  any  claims 
to  practical  utility,  however  venerated 
by  hoary  traditions.  The  old  perpen- 
dicular has  no  reference  to  the  measure- 
ment for  tonnage,  capacity  or  displace- 
ment, nor  is  it  the  length  on  any  of  the 
decks,  being  placed  at  the  termination 
of  a  sheer  line  at  the  height  of  the  cross 
seam,  hence  it  will  be  rendered  appa- 
rent at  once,  that  although  two  vessels 
might  be  built  by  the  same  moulds,  and 
by  the  same  man  if  you  please,  by  ele- 
vating or  depressing  the  sheer  forward 
in  one  vessel,  the  other  would  be  of  a 
different  length  between  those  points, 


DISPLACEMENT    OF    THE    OCEAN    STEAMER. 


PLATE  2. 


c  E 

B  •>  I 


CALCULATIONS 


SIXTH  WATER  LINE. 


Jialf 

Seel.  I.realili. 

40=  16  Xl=  1.6  X  0=     0  0 
36=  6  35X1=25.4  X   1=  25.4 
3*=  9.35X2=19.7  X  2=  39  4 
28=I2.01X4=43.16X  3=114  19 
24=13  75X2=27,5  X  1=110. 
20=15.     X1=60      X  5=300. 
16=16.     X2=32.     X  6=192. 
12=16.9  Xl=67  2  X   7=170  1 

8=17  12X2=34  S4X  6=279  72 

4=I7.S  X4=71.2  X  9=610.8 
M=1S.08X2=36.16X10=361  6 
D=1S.04X4=72. 16X1 1=793.76 
H=I7  85X2=35  7  X12=428.4 
.11=17.5  X4=70.  X13=910. 
Q=16  78X2=33  56X11=469.84 
[7=15.75X4=63.  X  15^915. 
Y=I13  XfcS  6   X16=457  6 

C=I2  4   X4=19C   X17=843.2 
£=10  05X2=211.1    XI9=361.3 

(=  7.55X4=30.2  X  19=573.8 
p=  4.9  Xl=  4.9X20=  98. 


CALCULATIONS 

FOR 
FIFTH  WATER  LINE. 


3)831.59       3)8444.2 


lialf 

Sect,  breadth. 

10=  15  Xl=  1.5  X  0=  0  0 
"=5.4  X4=21.6  X  1=216 
32=  875X2=17.5  X  2=  35. 
28=11. 12X1=44. 48X  3=133.41 
21=12  9  X2=25  S  X  4=103.2 
20=14  4  X4=S76  X  5=2-^ 
16=15  54X2=31. 08X  6=186  48 
12=16.49X4=65  92X  7=461.44 

8=17  15X2=31  3  X  B= 

4  =  I7S6XI=70.21X  9=632.16 
i>=17  83X2=35  65X10=316  6 
D=17  3  X4=71.2  XH=783  2 
H=17.6  X2=35.2  X12=122.4 
M=I7  1  X4=63.4  XI3=889.2 
(1=16  3  X2=326  XI4=456.4 
l"=l>  03X4=60.32X15=904  8 
V=13  54X2=27.08X16=433.28 
I  58X4=16.32X17=787.44 
g=  9:12X2=18.61X18=335  52 

(=  6.9  X4=27  6  X19=S24.4 
p=  4.46X1=  4.46X20=  89.2 


CALCULATIONS 

FOB 
FOURTH  WATER  LINE. 


277.19  2814.73 

Bet.  sect.    X  10  ft.  squar.  100 

J  or.  aftofp277l.9 
I  Qrea  for- 
ward of  p  -i-  45.3 
ft  area  2317.2      )290809.33 

From  serf.  40  to  cen- 
tre  of  gravity,  103.2-2  ft 


281473. 
9336.33 


Concent  forward  of  p. 
p=4.9  Xl=  4.9  X0=  0  0 
(=2.67X4=10.68X1=10.68 
Stem=  .4  XI=    .4  X2=    .8 


3)15.93 
5.33 


3  11.48 
3.83 


ft  dist.  from  p 

to  stem 
ft  area  for.  ofp  45^3       )276.71 
From  p  to  ceri.  ofgrav.      6  1  ftT 
From  40  to  p  200,    ft. 


206  1 
ft  area  forward  of  p  45.3 

i  horizontal  moments  9336.33~~ 


3)797.5         3)3118.16 


26583  2706.05 

Betw.  sec.Xlotj.squar.Xloo 


bait 

SecL  breadth. 

40=  1.2  Xl=  12  X  0=  0.0 
36=  4.4  X4=17.6  X  1=  17.6 
32=  7  3  X2=14.6  X  2=  29.2 
:  9.7  X4=38.8  X  3=116  4 
21=11.75X2=23  5  X  4=  91. 
20=13.5  X4=54.  X  5=270. 
16=41.85X2=29  7  X  6=178.2 
12=15.9  X4=636  X  7=445  2 
16.7  X2=33  4  X  8=267.2 

4=17  25X4=69.     X  9=621. 
(•7=17  53X2=35  06X10=35116 
D=175  Xl=70.     Xll=770. 
H=17.3  X2=34.S  X12=415  2 
M=16  64X1=66  56X13=865. 23 
0=15.65X2=31.3  X14=4 
U=14. 25X1=57.     X15=S55. 
Y=12.55X2=2I.l   X16=101.6 

C=10.53X4=12. 32X17=719  14 
g=  8.45X2=16.9  X18=304.2 

t=  6.25X4=25      XI9=475. 
Jl=  4.     Xl=  4.     X20=  80. 


CALCULATIONS 

FOR 
THIRD   WATER  LINE. 


ft  ar.  aft  ofp  2653  3  270605. 
ft  area  for- 
ward of  p      40  53  8359.49 
ft  area            2698.83  )278964.48 

From  40  to  centre 

of  gravity  103  47 


Contents  forward  of  p. 
P=4  46X1=1.46X0=  0.0 
(=2.45X4=9.8  Xl=  9.8 
Stem  =    4   XI=  .4   X2=    .8 


3)14.65        3)10.6 


4  89  3.53 

1  (list   betw.  p 
ami  stem       8  3  squar.  68.89 


40.58         )243.18 
From  p  to  een.  ofgrav.     6.  feet. 
From  40  to  p  200.  feet. 


206- 
4  area  of  part  forward      40  58 


ft  horizontal  momenta  8359.43 


3)753.24       3)7713.32 

251. OS          2571.11 
Betw.  SCC9.X10 100 

2510.8 

i  area  for- 
ward     -!-  36.69 

1  area        2517.49   )-26486iT2 
From  40  to  centre 
of  gravity 103.89 


half 
Sect,  breadth. 

10=  1.     Xt=  1.     X  0=    00 
"■    :  3.5  X4=14.     X  1=  14. 
32=  6.     X2=12.     X  2=  24. 
28=  8.15X4=32.6  X  3=  97.8 
21=10.1   X2=20  2  X  1=  80.8 
20=12.     X4=49.     X  5=240. 
16=13  58X2=27  16X  6=162.96 
12=14.95X4=59.8  X  7=113  6 

8=16.     X2=32.     X  8=256. 

4=16.75X1=67.     X  9=603. 
(9=17.1  X2=31.2  X10=342. 
D=17.      X4=68.      XI  1=748. 
H=16  65X2=33  3  X12=399.6 
M=15.9  X4=63  6  X13=826  8 
0=14.67X2=29. 34X14=410.67 
U=13.2  X4=52.S  X15=792. 
Y=ll  42X2=22.84X16=365.64 

C=  9.5  X4=39.     X17=616. 
g=  7.5  X2=15.     X18=270. 

1=  5.44X1=21.76X19=413.44 
P=  3.4  Xl=  3.4   X20=  68. 


CALCULATIONS 

FOR 
SECOND  WATER  LINE. 


3)696. 


3)71794 


257111. 
Jr  7555.2 


232.  2393.13 

Bet.  sec.  ft.  Xlo.  squar.  100. 
~  239313. 
6174.75 


2320. 
30. 


ft  area  for 
ward 

ft  area  2350.        )245497.75 


half 
Sect,  breadth. 

40=    .75X1=     75X  0=    0.0 
36=  2.5  X4=10.     X  1=  10. 
32=  4.42X2=  8.84  X  2=  17  63 
28=  6.32X4=25.28X  3=  75.84 
24=  8.25X2=16.5  X  4=  66. 
20=10.     X4=I0.     X  5=200. 
16=11.8  X2=23  6  X  6=1416 
12=13.45X4=53.8  X  7=376.6 

8=14  3  X2=29  6  X  8=236  3 

4=15  78X4=63. 12X  9=56S03 
S=I6 -25X2=32  5  X  Hi=325. 
D=16  08X1=64.32X11=707.52 
H=15.55X2=3l.l  X12=373.2 
IW=14  6  X4=S8.4  XI3=759  2 
Q=I3  3  X2=26.6  X  14=372.4 
17=11.7  X4=16.8  X15=702. 
Y=  9.92X2=19.84X16=317  41 

C=  8.15X4=326   X17=554.2 
g=  6  33X2=12.66X18=227.88 

(=  4.58X4=18.32X19=2357.08 
p=  2.83X1=  2.83X20=  56.6 

3)617.46       3)644452 


CALCULATIONS 

FOR 
FIRST  WATER  LINE 


half 
Sect,  breadta. 
40=     .6  Xl=     .6X0=     0.0 

=  1  5  X4=  6.     X   1=    6. 
32=  2.55X2=  5.1   X  2=   10  2 
29=  3.9  X4=15.6  X  3=  46  8 
21=  5  56X2=11. 12X  4=  44.49 
20=  7  42X4=29  63X  5=149.4 
16=  9  4   X2=I8.8  X  6=11-2  8 
2=11  3   X4=45.2  X  7=316.4 
8=12  92X2=25. 84X  8=206  72 
4=14.24X4=56  96X  9=512.64 
(2t=14.8  X2=29.6.X1IJ=296. 
0=14  55X4=53.2  Xll=640.2 
H=137  X2=27.1   X  12=223  9 
.11=1-2  55X1=50  2  X13=652.6 
Q=ll  08X2=22.16X14=310.24 
U=  9  55X4=39  2  X15=573. 
Y=  7.9  X2=158  X16=252.8 
c=  6  33X4=25  32X17=430.44 
g=  4.8  X2=  9  6  X18=I72  8 
(=  3.1   X4=13  6  X19=2SS4 
p=  2.08X1=  2  08X20=  41.6 


20582  2148.17 

Betw.  sects.   10.  squar.  100. 


Contents  fonoard  of  p. 
JJ=4.     Xl=4.     X0=  0  0 
(=2.3  X4=9.2  Xl=  9.2 
Stem=  .4  Xl=  .4  X2=    .8 


From  40  to  centre 
I    ofgravity 


101.46 


ft  dist.  from  p 

to  stem  8.1     sq.  65.61 

ft  area  36.69       7218.48 


From  p  to  cen.  ofgrav.     5.92 
From  40  to  p  200. 

205.92 

ft  otea  of  part  forward  X  36.69 


Contents  forward  of  p. 

p=3  4  Xl=3.4   X0=  0  0 

(=1.9  X4=7.6  Xl=  7.6 

Stem=  .4  Xl=  .4  X2=     .8 


3)11.4 


3  3.4 


J  ilist.  fromp 
to  stem 


2.8 
sq.  62.41 


ft  horizontal  moments  7555.2 


DISPLACEMENT 

TWO  FEET  ABOVB 
SIXTH  WATER   LINE. 


40=.2  5  Xl=  2 
36=  7.8  X4=31 
32=ll.22X-2=22. 
28=13.2  X4=52 
21=146  X2=29. 
20=15.6  X  1=6-2 
6=16.45X2=33 
2=17.1  Xl=68 
8=17  6  X2=3S 
4=17.9  X4=71, 
(Xfc-18  0SX2=36 
D=I9  03X4=72 
H=I304X2=36 
M=178  X4=71 
0=17  3  X2=34 
IJ=I65  X4=66 
Y=15. 25X2=30 
C=I3.35X4=53 
g=ll.  X2=22. 
(=8  4  X4=33 
p=  5  5  X2=ll 
1=  2.65X4=10 


5  X  0=  0 
2  X  1=  31 
44X  2=  44. 

8  X  3=158. 
2  X  1=116. 
4  X  5=312. 

9  X  6=203. 

4  X  7=478. 
2  X  B=28l. 

6  X  9=614 
16X10=361 
32X11=795. 
08X12=432. 
2  XI  3=925. 
6  XI4=184. 

X  15=990. 

5  XJ6=488 
1    X17=907. 

X  18=396. 

6  X19=638 
X20=220. 

6   X21=222. 


3)837.1         3)9134.36 

2957  3044.79 

Bet.  sects.      10.  6quar.  100, 


28  ft  area  2957.         J301479. 

27  From  40  to  cen  ofgrav.  102.97 


From  p  to  cen.  ofgrav.      5.82 
From  40  top  200. 

,  ,  205.82 

ft  area  of  part  forward       30. 

ft  horizontal  momenta  6174.75~~ 


1  ar.aft  of  p  2058.2        214817.3 
ft  area  for- 
ward of  p    21.47         5017.57 


ft  area 

From  sec.  40  to  cen 
tre  of  gravity 


2082.67     )2I9834.87 


105  55 


Contents  forward  of  p. 
P  =2.83X1=2.83X0=  0.0 
(=1  61X4=6,44X1=  6,44 
Stem=  .4   Xl  = 


1=  .4   X2=    .8 

3)9  67 

3)7.24 

3.22 
7.6 

2.41 

57.67 

24.47 

)123  6 

From  p  lot-en  ofgrav 
From  40  to  p 

I  sos  ds 

ft  area  of  part  forward      24,47__ 
1ft  horizontal  moments  501757 


3  507  06       3'5361  32 

169.02  1797.1066 

Betw.  sects.  10    squ^r  too 


1  ar.  aft  of  p  1690.2 
i  area  for- 
ward ofp    17.85 

1  area 


179710ft, 
366*52 


1708.05     )I82379.I9 


106  77 


Contents  fortoard  ofp. 
p  =2.03X1=2.08X0=  0  0 
(=1.24X4=4.96X1=  4.96 
Stem=  .4   Xl=  .4   X2=    .8 


3)7  44 


3  5  76 


17.85         )99.53 


From  plo  cen.  of  grav.      5  52 
From  40  to  p  200. 


205.52 
17  35 


1  horizontal  momenta  3fifi9  52 


CALCULATION  OP  THE   CENTRE  OK  DISPLACEMENT. 


half 
arcaa. 
Sixth  Water  Line 2817.2    Xl=    2817.2    X 

Fifth  Water  Line 2698.68  X  4  =  10795.S2  X  1  =  10795,52 

Fourth  Water  Line 2547.49  X  2  =    6094.93  X  2  =  10189.96 

Third  Water  Line 2350.      X4=    9400.      X  3  =  28200. 

Second  Water  Line  •■•■2082.67  X  2  =   4165.34  X  4  =  16661.36 

First  Water  Line 1708.05X4=    6832.2    X  5  =  34161. 

K'°l2l 106.5     Xl=      106,5     X6=      639. 

3)39211.74  3)100646.84 

13070.58  33548.95 

Distance  between  Water  Lilies 1.5       squared  2.25 

19605,87  )75485137 

Centre  ofgravity  below  Six!  li  Water  Line 3.35  ft 

Exponeut  of  Capacity; 

feet  breaihh  cubic,  fact. 

Length  between  perpcndiculara 218  5    X    36.2    X    9    =   71179  3— thle 

Divided  into  the  entire  displacement mlt7,    _   .65-tho  Enponent  of  Capacity 


o-   tu  iir  r  ■  ■  horirontnl  momeiiu. 

bixth  water  Line 29030933  x  1=   290809.33 

Fifth  Water  Line 278964.49  X  4  =  1115957  92 

Fourth  Wutcr  Line 261666.2    X2=    529332.4 

Third  Water  Line 2454S6.05  X  4  =    931952.2 

Second  Water  Lino  219934.87X2=    439669  74 

First  Water  Line 192379.18  X  4  =    729516.72 

Keel 11310.3    XI=      113103 

39211.74)4098143  61 
From  10  to  centre  ofgravity IOt.5l  ft 


■  •mi.    of  Effort 

FROM 
SIXTH  WATER  LINE 


Tube-  of 

Sect 

breadths 

40 

1.6 

4.09X1=        4  09 

36 

0  35 

2i6  05X4=  1024.2 

32 

9  85 

955  67X2=  1911  34 

■29 

1204 

1715  3  X4=  69912 

24 

13.75 

2599  6  X2=  5199.2 

■211 

IS. 

3375.     X4=  13500. 

11, 

16. 

4096.     X2=  8192 

12 

16  8 

4741  6  X4=19966.4 

3 

17  42 

5236  2  X2=10572.4 

4 

178 

5639  8  X4=2-2559.2 

■' 

18  09 

5910  1   X2=1I820.2 

1) 

18  04 

5910.     X4=23640. 

II 

1785 

5687  4   X2=1I374.8 

M 

175 

5359  4   X4=21437.6 

« 

16.79 

4724  7  X2=  9449.4 

11 

15.75 

3907.     X4=15629. 

Y 

143 

2924.2  X2=  5849  4 

c 

12  1 

1906.7  X4=  76-26  8 

it 

10.05 

1015  1   X2=  2030  2 

I 

7  55 

430  37X4=  1721  19 

P 

49 

11765X2=    235.3 

t 

225 

1139X4=      4556 

0. 

0      Xl=        0 

3  199767.77 
66599.2^ 

Section  distances             10  feet 

665992  5XS 

221964.2 

V-Tide  cubic  dis- 
placement 3mi.7i*U39Q8Z 

<""rn  (t!'efroft  obnve 
centre  ofgravity  11.39  ft 


. 


Rfl 


MARINE    AND    NAVAL    ARCHITECTURE 


S9 


although  the  same  model;  but  this  is  not 
all :  the  longest  vessel  between  the  per- 
pendiculars is  not  always  the  longest  on 
the  load-line,  and  although  a  ship  might 
be  considered  longer,  and  as  a  conse- 
quence be  expected  to  sail  faster,  be- 
cause she  measures  more  between  the 
perpendiculars  than  another,  she  would 
perhaps  in  truth  be  shorter  than  her 
rival.  Having  cleared  all  the  obstruc- 
tions that  have  a  tendency  to  mystify 
this  subject,  we  shall  pursue  the  expo- 
sition of  the  centre  of  effort — the  cubes 
of  the  breadths  are  multiplied  as  already 
explained  in  the  first  and  last  sections 
by  1,  and  the  intermediate  sections  are 
multiplied  by  4,  2,  4,  2,  &c.,  alternately, 
the  products  are  added,  and  their  sum 
is  divided  by  3,  the  quotient  is  multi- 
plied by  10,  the  distance  in  feet  between 
the  sections,  this  product  is  multiplied 
by |,  and  the  last  product  is  divided  by 
the  displacement  in  cubic  feet,  the  quo- 
tient will  be  the  height  in  feet  above  the 
centre  of  displacement,  viz.,  11.32  feet; 
we  have  also  shown  in  another  column 
the  displacement  of  the  next  two  feet 
above  the  sixth  water-line,  which  would 
reduce  the  distance  from  the  centre  of 
effort  to  the  centre  of  displacement  to 
9  feet.  The  draught  of  water  would  not 
be  heavy  even  if  the  line  above,  or  the 
line  11  feet  above  base  were  adopted  as 
the  load-line  of  flotation,  being  but  12 
feet ;  this  however  would  materially  re- 


tard her  speed,  which  in  ocean  steamers 
is  one  of  the  most  important  considera- 
tions ;  the  author  regards  an  ocean 
steamer  that  is  deficient  in  speed  as 
scarcely  less  than  a  total  failure,  how- 
ever many  other  good  qualities  she  may 
possess.  We  shall  doubtless  be  able  to 
see  at  a  glance  what  is  the  capacity  of 
this  steamer,  at  the  twelve  feet  draught, 
the  half  area  of  the  9  feet  line  above 
base  =  2S17  feet,  and  the  half  area  of 
the  11  feet  line  =  2957,  which  added 
together  and  multiplied  by  2  feet,  the 
distance  between  them,  gives  11548  cu- 
bic feet,  this  added  to  39211  cubic  feet,  the 
displacement  between  the  9  feet  line  and 
the  base,  gives  50759  cubic  feet  below 
the  12  feet  draught,  which  multiplied 
by  eighteen-seventeenths,  gives  the  ad- 
ditional displacement  for  the  plank,  ma- 
king the  number  of  cubic  feet  53745  ; 
this  sum  multiplied  by  five-ninths  for 
the  weight  of  the  vessel,  we  have  re- 
maining nearly  30000  cubic  feet  for 
the  entire  capacity;  this  sum  divided 
by  35,  the  number  of  cubic  feet  in  a 
ton,  we  have  857  tons ;  if  the  draught 
of  water  were  increased  to  12j  feet,  the 
capacity  would  be  increased  about  S5 
tons,  making  in  all  942  tons.  We  shall 
now  show  the  manner  of  finding  the 
ratio  of  the  exponent  of  capacity  for 
the  several  water-lines,  and  from  the 
entire  displacement ;  first,  to  find  the 
exponent  of  the   sixth  water-line,   set 


12 


90 


MAI!  INK    AND    NAVAL    ARC  H  I  T  K  ( '  T  I    RE. 


down  the  length  between  the  perpen- 
diculars, and  multiply  the  same  by  half 
of  the  main  breadth,  and  divide  the  pro- 
duct into  the  half  area  of  the  same  wa- 
ter-line, the  result  furnishes  the  expo- 
nent for  that  line  ;   example — 


Length.       1  Breadth. 

218  X  18,0S  =  411l.ll 


J  Area- 

2817.2  =  ;68 


which  is  the  exponent  of  the  sixth  wa- 
ter-line, and  the  remaining  lines  may 
be  obtained  in  the  same  manner.  To 
find  the  exponent  of  capacity  for  the 
entire  vessel  below  the  sixth  water-line, 
multiply  the  length  between  the  per- 
pendiculars by  the  breadth,  and  that 
product  by  the  distance  from  the  base 
to  the  sixth  water-line  ;  the  last  pro- 
duct, which  is  cubic  feet,  must  be  di- 
vided into  the  whole  displacement  be- 
low the  sixth  water-line,  and  the  quo- 
tient is  the  exponent  of  capacity  ;  ex- 
ample— 

Length.         Breadth.        Cubic  Feet.     Whole  Displacement.  Cubic  Feet. 

218.5  X  36.2  =71187.3  39211.74  -H  71187.3  =.55 

the  exponent  of  capacity. 

Did  we  deem  it  necessary  we  might 
show  another  mode  of  calculating  dis- 
placement,  but  having  occupied  more 
than  a  proportionate  space  in  our  ex- 
positions of  this  subject,  we  deem  it 
wholly  unnecessary,  and  shall  proceed  in 
our  efforts  to  frjrnish  some  information 
upon  such  other  parts  of  this  important 
fabric  as  have  been  set  apart  for  this 
chapter. 


Few,  if  any  of  those  who  have  the 
reputation  of  being  skilled  in  draught- 
ing vessels,  can  by  any  power  of  con- 
ception form  a  correct  idea  of  the  form 
of  the  vessel  drawn  in  its  rotundity,  or 
if  they  possess  this  rare  endowment,  it 
is  impossible  to  convey  in  language  the 
same  to  a  second  or  third  party;  in 
Europe,  ship-owners  as  well  as  builders 
have  found  it  necessary  to  learn  and 
practice  drawing,  that  they  might  be 
able  to  acquire  a  proper  conception  of 
the  form  of  vessels  from  the  same,  and 
with  the  aid  of  a  work  on  naval  archi- 
tecture many  have  become  proficient  in 
the  art,  while  they  really  knew  much  less 
of  shape  in  its  rotundity  than  the  ope- 
rative mechanic  in  the  United  States, 
who,  in  obedience  to  his  own  notions, 
has  whittled  out  his  first  model.  It 
will  be  at  once  apparent  to  the  think- 
ing-man, that  it  is  impossible  to  repre- 
sent two  curves  in  a  single  line,  or  to 
delineate  the  shape  of  a  line  in  two  ways 
without  making  two  lines;  the  most  pro- 
found mathematician  will  admit  this, 
and  still  further,  it  is  difficult  to  retain 
two  shapes  in  the  eye  at  the  same  time, 
in  all  their  relative  proportions.  While 
the  present  practice  is  adhered  to,  of 
determining  the  shape  we  want  by  the 
eye,  we  can  scarcely  suit  ourselves  on 
a  plane,  or  if  we  do  on  the  draught  we 
are  not  suited  in  the  vessel,  because 
she  is  not  exactly  what  we  expected. 


M A R I N E    A  N  D    NAVAL    ARCHITECTURE 


91 


This  discrepancy  iii  the  mode  can  only 
be  remedied  by  drawing  a  perspective 
plan,  which  must  of  necessity  form  a 
second  drawing,  the  principal  objection 
to  which  exists  in  the  fact,  that  it  is 
quite  an  extensive  operation,  and  un- 
less the  work  is  performed  in  strict  ac- 
cordance with  the  laws  of  perspective, 
which  pertain  to  geometrical  science, 
a  correct  idea  cannot  be  given  ;  thus  it 
will  be  perceived  that  the  draught  alone 
does  not  furnish  an  index  to  rotundity 
in  ships,  and  although  useful,  and  in 
many  respects  far  more  convenient,  yet 
for  the  single  purpose  of  delineating  the 
form  of  a  vessel  by  the  eye,  the  model 
is  incomparably  its  superior,  and  to  its 
invention  are  we  measurably  indebted 
for  much  of  our  success  in  preserving 
an  equilibrium  against  the  conflicting 
interests  that  surrounded  us.  The  his- 
tory of  commerce  has  witnessed  no 
greater  achievement  than  is  furnished 
in  this  ensign  of  mechanical  genius. 
By  its  use  we  have  been  enabled  to 
wring  reluctant  laurels  from  surround- 
ing  nations,  who  have  paid  a  just  tri- 
bute to  this  proud  emblem  of  Ameri- 
can skill.  That  the  model  is  com- 
pletely adapted  to  our  wants  must  be 
admitted  even  by  the  casual  observer, 
when  he  discovers  that  every  part  of 
the  vessel  may  be  exhibited,  all  the  pro- 
portionate lengths,  breadths  and  depths, 
every  line  may  be  seen  in  its  appropri- 


ate place,  it  exhibits  not  only  the  form 
but  a  ready  mode  of  obtaining  tables  for 
the  loft,  and  is  for  the  purposes  deli- 
neated, to  the  draught,  what  statuary 
is  to  a  written  description  of  the  physi- 
cal man,  the  latter  the  shadow,  the  for- 
mer the  substance.  But  there  is  ano- 
ther particular  in  which  the  model  ex- 
hibits its  superior  advantages  over  the 
draught,  an  expansion  plan,  or  a  ves- 
sel expanded  on  a  plane  for  the  pur- 
pose of  showing  the  true  shape  of  every 
plank  (or  for  obtaining  the  spiling  of 
every  plank  as  if  taken  from  the  ship 
on  a  rule  staff)  cannot  be  furnished 
from  the  draught.  There  is  not  a  work 
extant  that  contains  a  correct  plan  of 
expansion  ;  it  requires  but  a  moment's 
reflection  to  discover,  that  if  a  sheet 
of  tea-lead,  or  some  similar  substance, 
were  brought  around  the  exterior  sur- 
face of  a  half  model,  and  the  lower  edge 
cut  to  the  base-line  or  side  of  the  keel, 
the  upper  edge  cut  by  the  lower  side  of 
the  rail,  the  ends  being  respectively  cut 
by  the  rabbets,  both  forward  and  aft 
along  the  cross  seam  and  quarter  piece; 
the  sheet  being  now  flattened  out,  it 
would  be  discovered  that  the  lower 
edge  is  not  straight  as  represented  in 
all  plans  of  expansion  by  naval  archi- 
tects. Every  mechanic  at  all  familiar 
with  the  operation  of  planking  knows, 
that  by  twisting  plank  the  (h\^vs  vary 
proportionately    from    a    straight    line, 


92 


MARINE    AND    NAVAL    ARCHITECTURE. 


and  as  there  is  no  strake  below  water 
on  the  ship  that  has  more  twist  than 
the  garboard  strake,  it  follows,  that  no 
strake  has  a  greater  departure  from  a 
straight  line  below  water  ;  and  although 
most  of  this  winding  is  found  at  the 
(nu\fi  of  the  vessel,  yet  it  would  be  found 
that  a  straight-lined  plank  would  re- 
quire hard  sets  to  make  it  seam  to  the 
rabbet  on  the  keel,  were  the  strake  in 
one  length  ;  the  model  makes  ample 
provision  for  this  discrepancy,  and  will 
furnish  the  shape  required,  as  will  be 
shown  in  its  proper  department.  The 
sni  (to  use  the  familiar  term)  that  in- 
creases so  fast,  as  we  ascend,  is  occa- 
sioned by  diminishing  the  strake  at  the 
ends.  We  shall  have  occasion  to  re- 
sume this  subject,  and  treat  it  more  at 
length  in  a  subsequent  chapter,  under 
its  appropriate  head. 

The  model,  we  have  said,  is  a  proud 
emblem  of  American  skill,  and  to  it  are 
we  indebted  for  much  of  our  success. 
Models  have  been  made  in  Europe  as 
early  as  the  middle  of  the  last  century ; 
but  they  were  what  would  be  recog- 
nized as  the  skeleton  model,  made  of 
pieces  representing  the  half  frames, 
and  are  neither  adapted  to  the  purposes 
of  building,  or  of  exhibiting  the  lines 
of  flotation.  The  invention  of  water- 
line  models,  like  many  others,  was  the 
result  of  mere  accident.  In  the  East- 
ern states,  and  in  the  British  provinces, 


men  who  were  acquainted  with  the  artof 
construction  upon  paper,  made  from  a 
block  the  form  of  the  vessel  they  intend- 
ed to  build,  which  was  cut  into  several 
transverse  sections;  those  sections  re- 
presenting frames,  were  then  expanded 
from  the  scale  upon  which  the  model 
was  made,  to  the  size  of  the  vessel ; 
and  frames  were  worked  out  to  which 
harpens  were  attached,  and  the  re- 
maining parts,  or  intermediate  spaces, 
filled  in  by  making  moulds  to  those 
harpens.  In  making  one  of  those  block 
models,  the  block  was  found  to  be  too 
small  to  give  the  required  depth,  to 
which  a  piece  was  added,  and  when 
finished  it  was  discovered  that  the  lon- 
gitudinal form  of  the  vessel  was  shown 
by  the  line  uniting  the  two  pieces  to- 
gether. The  question  at  once  arose,  if 
one  seam  was  an  advantage  two  would 
be  a  still  greater  ;  and  as  early  as  1790 
water-line  models  were  made  for  build- 
ing purposes.  The  author  has  seen 
the  model  of  a  ketch,  called  the  Eliza, 
190  tons  burthen,  which  was  launched 
in  the  middle  of  June,  1794  ;  this 
model  was  made  in  three  pieces,  by 
the  scale  of  one  quarter  of  an  inch  to 
the  foot,  84  feet  keel,  24  feet  beam, 
and  9  feet  hold,  and  may  be  seen  in  the 
rooms  of  the  East  India  Marine  So- 
ciety, at  Salem,  Mass.  This  model  has 
been  preserved  on  account  of  the  re- 
markable qualities  the  vessel  possessed 


MARINE    AND    NAVAL    ARCHITECTURE. 


93 


for  sailing  fast ;  she  was  built  by  Mr. 
Briggs,  the  same  builder  who  built  the 
frigate  Essex,  at  Salem.  The  first 
model  made  in  this  city  was  by  David 
Seabury,  which  was  soon  followed  by 
others.  The  Ohio,  seventy-four,  built 
for  the  Government,  from  a  model 
made  by  Stephen  Smith,  of  this  city, 
then  an  apprentice  to  Mf.  Eckford, 
was  among  the  first  vessels  built  from 
the  model  in  the  immediate  vicinity  of 
New-York  ;  its  advantages  were  soon 
appreciated,  and  the  draught  was  laid 
aside,  and  has  at  length  grown  ob- 
solete. 

Before  entering  upon  the  responsible 
duties  of  delineating  the  construction 
of  models,  we  shall  render  our  readers 
a  service  by  furnishing  them  with  ma- 
terials for  reflection,  from  the  frame- 
work of  30  years  experience  in  build- 
ing ships,  by  one  whose  opinion  we 
have  had  occasion  to  notice  in  the  first 
chapter.  To  an  inquiry  made  of  se- 
veral of  the  builders  of  this  city,  the 
author  received  but  one  reply,  viz.,  the 
eye  is  the  text-book  for  modelling  ves- 
sels. 

The  following  letter  we  have  deem- 
ed worthy  not  only  of  a  place  in  this 
work,  but  of  an  inscription  on  the  tablet 
of  the  memory  of  all  such  ship-owners 
or  others  as  may  suppose  they  know 
all  that  is  worth  knowing  about  build- 
ing and  masting  ships : 


"  New- York,  January  20,  1850. 
"  Mr.  J.  W.  Griffiths  : 

"  Dear  Sir,— 

"  I  am  truly  gratified  to  know  of 
your  intention  of  publishing  a  treatise 
on  the  subject  of  Naval  Architecture. 
It  is  a  work  much  needed.  Your  labors 
in  this  cause  already  merit  the  thanks 
of  the  profession,  and  I  trust  that  your 
present  undertaking,  as  it  deserves  well, 
so  will  it  fare  well  at  their  hands,  and 
of  the  public  generally,  Avhose  safety 
and  interests  are  so  deeply  involved  in 
everything  which  has  for  its  object  the 
promoting  of  scientific  knowledge  in 
relation  to  this  subject. 

"  I  suppose  there  is  no  class  of  me- 
chanics in  the  world  who  have  labored 
at  such  disadvantages  in  the  practice 
of  their  profession  as  ship-builders.  Al- 
though ship-building,  as  a  practical  art, 
has  been  in  existence  for  thousands  of 
years,  yet,  as  a  matter  of  science,  little 
or  nothing  has  been  done  in  its  favor 
until  quite  lately.  It  is  still  true,  that 
with  the«exception  of  those  conflicting- 
rules  of  tonnage,  and  that  ill-advised 
dictation  of  owners,  by  which  he  is 
hampered  and  vexed,  rather  than  as- 
sisted, each  individual  modeller  has 
little  else  besides  his  own  taste  and  eye 
to  guide  him.  That  the  subject  is 
capable  of  being  brought  under  more 
general  rules,  like  other  departments 
of    mechanics — in    other   words,    that 


94 


MAK1NE  AND  NAVAL  ARCHITECTURE. 


the  subject  of  Naval  Architecture  may 
be  made  a  science  as  well  as  an  art, 
no  builder  of  experience  has  the  least 
doubt.  And  ship-building  can  never 
be  on  a  par  with  other  practical  pro- 
fessions until  such  is  the  case. 

"Doubtless,  here,  as  in  other  depart- 
ments, practical  men  ought  to  look  for 
a  certain  degree  of  information  from 
the  labors  and  studies  of  scientific 
men.  The  general  laws  of  the  resis- 
tance of  bodies  in  fluids  ;  the  laws  of 
motion  ;  of  the  application  of  forces ; 
the  laws  of  gravity  and  dynamics,  are 
fixed  laws  of  nature,  and  should  be  as 
familiar  to  the  ship-builder  as  the  laws 
of  heal  and  steam  to  the  steam-engine 
builder.  They  should,  indeed,  be  es- 
pecially familiar  to  him,  from  the  very 
fact,  that  the  conditions  and  circum- 
stances of  their  application  are,  in  his 
case,  so  variable — almost  infinitely  so. 
This  it  is  that  makes  the  problem  of 
modelling  so  uncommonly  difficult. — 
The  question,  in  each  particular  case, 
is  involved  (besides  the  preliminary 
conditions)  with  so  many  possible  ac- 
cidents, altogether  beyond  the  builder's 
control,  and  which  must,  nevertheless, 
come  into  the  consideration  of  his 
model.  When  a  mechanic  builds  a 
steam-engine,  a  sugar  or  a  cotton 
factory,  as  soon  as  his  work  is  put  up 
it  is  fixed  and  done.  But  when  a 
builder   launches    a   ship,  it  is  entirely 


different ;  the  thing  is  to  be  both  at  rest 
and  in  motion,  liable  to  a  thousand 
varying  circumstances.  His  vessel  is 
required  to  be  strong,  to  be  swift,  to  be 
capacious;  to  act  well  in  sudden  and 
rough  weather,  as  well  as  in  smooth: 
and  to  act  well  also  upon  the  possible 
and  often  actual  conditions  of  mis- 
placed weight,  loss  of  spars,  and  mis- 
management or  incapacity  of  those  in 
whose  hands  she  is.  In  addition  to  all 
this,  she  is  often  required  to  be  pre- 
viously modelled,  in  accordance  with 
the  fancy  of  some  conceited  owner, 
who,  having  made,  perhaps,  a  single 
voyage  in  a  ship, — and  perhaps  not 
even  that, — thinks  he  knows  more  than 
all  the  builders  in  the  world,  and  he- 
comes  ambitious  of  Inning  his  ships 
pass  for  his  own,  not  only  as  owner  but 
as  inventor  and  builder  also.  Then, 
too,  the  ship-builder  is  not  always  at 
liberty  to  carry  out  his  own  idea  as 
regards  the  sparring ;  but  after  sub- 
mitting his  list  of  spars,  is  often  put  to 
the  mortifying  necessity  of  making 
changes,  which  he  knows  must  injure 
the  action  of  the  ship.  Thus,  not  only 
his  general  art,  but  his  individual  re- 
putation, is  at  the  mercy  of  those  who 
have  no  more  than  a  mere  smattering- 
of  knowledge.  Of  those  who,  while 
they  think  they  know  everything,  are, 
in  reality,  so  unskilled  and  ignorant  as 
to  be  unable  to  detect  differences  in   a 


MARINE    AND    NAVAL    ARCHITECTURE 


95 


model  sufficient  to  .alter  the  character 

of  a  vessel. 

"  It  is  not  ship-merchants,  nor  is  it 

always  ship-captains,  that  are  possessed 
of  that  cultivation  of  the  eye  which  is 
necessary  in  order  to  pass  judgment  at 
a  glance,  upon  the  merits  of  any  par- 
ticular model.      This  is  a  thing  which 
is  only  to  be  acquired  by  the  practice, 
not  of  looking  at,   or    being    ever    so 
conversant  in    other  respects    with    a 
ship,  but  of  making  ships.     It  may  be 
safely  said  that  his  judgment  of  a  mo- 
del is    not  worth   much,  who    cannot 
make  a  model.      And  those  who  are  so 
unwise  as  to  think  they  are  qualified  to 
control  the  mind  of  a  builder  in  these 
respects,    should  learn    to    be    modest 
enough  to  admit  the  truth  of  the  above 
observation.      They  would  find  it  vast- 
ly to  their  interest  to  do  so.     We  shall 
never   generally   get    first-rate    vessels 
until  owners  and  others  shall  be  willing 
to  remain  in  their  own  departments, and 
give  builders  the  credit  of  being  suffi- 
ciently informed  in  theirs.      Let  them 
give  us  the  size,  that  is,  the  capacity, 
and  the  object  of  the  vessel  they  wish 
to  contract  for,  and  then  let  us  alone. 
This  is  all  we  ask,  and  we  will  pledge 
ourselves  hereafter  to  give  them  better 
ships,  without  their  assistance,  than  has 
hitherto  been  done  with  it  ;  and  the  re- 
sult will  very  quickly  show  it  to  be  so. 
"  It   appears  to  me,  therefore,  that 


the  main  thing  to  be  done  in  order  to 
promote  the  science  of  ship-building,  is 
to  get  rid  of  those  unnecessary  re- 
straints which  have  been  heretofore 
cramping  the  labors  of  builders,  and 
preventing  them  from  carrying  out 
their  own  ideas  in  the  practice  of  their 
profession.  In  the  first  place  I  would 
advise  the  advocacy,  by  your  treatise, 
of  an  International  tonnage  law.  Let 
the  rule  of  measurement  be  that  which 
takes  in  the  actual  capacity  of  the 
vessel.  This  is  the  only  sensible  rule, 
and  the  only  one  which  will  leave  mo- 
delling free.  How  perfectly  absurd  is 
it,  that  a  builder  should,  at  this  day,  be 
subjected  to  a  rule  of  tonnage  meas- 
urement, which,  if  he  were  to  follow 
it,  would  require  the  general  propor- 
tions of  his  vessel  to  be  the  same  that 
were  in  vessels  at  the  time  of  Crom- 
well ! 

"  In  the  next  place,  let  builders  be 
left  free  of  the  fancies  and  conceits  of 
owners  and  others.  Let  them  be  sup- 
posed to  know  their  own  business  best, 
and  have  no  other  requirements  ex- 
cept the  general  terms  of  the  contract, 
to  hamper  them.  Then  would  they  be 
on  a  par  with  other  mechanics,  to 
make  observations,  and  to  adopt  the 
results  of  experience.  I  have  said, 
that  builders  are  to  look  to  the  labors 
of  science  for  assistance.  In  many  re- 
spects they  are,  but  by  no  means  to  the 


96 


M  WtlNE    AND    NAVAL    ARCHITECTURE 


same  extent,  as  other  practical  men. 
All  science  depends  upon  experiment ; 
but  the  only  adequate  experimenters  in 
this  matter,  are  the  builders  themselves, 
together  with  the  assistance  which  they 
derive  from  captains  and  sailors.  It  is 
not  in  the  power  of  an  experimenter, 
with  cut  blocks,  in  a  pond  of  smooth 
water,  and  with  artificially  applied 
forces,  to  determine  the  best  model  for 
a  given  end.  It  is  a  very  easy  thing  to 
build  an  ideal  ship  that  shall  be  perfect ; 
but  to  build  a  ship  to  go  to  sea,  and 
carry  cargo,  and  be  exposed  to  the  ac- 
cidents of  shore  and  ocean,  is  a  very 
different  thing.  Scientific  experiments 
upon  land,  of  the  kind  mentioned,  are 
certainly  in  their  place,  and  have  help- 
ed us  to  decide  many  important  ques- 
tions ;  and  properly  conducted  will  help 
us  to  decide  more.  But  still  the  only 
adequate  experimenters  in  ship-build- 
ing are  those  who  make  and  sail  ships. 
The  only  sufficient  elements  in  the  ex- 
periment are  with  the  ships  themselves; 
and  the  only  fair  scene  of  experiment 
is  the  ocean  upon  which  those  ships 
are  to  sail,  and  to  whose  accidents  they 
are  liable.  The  great  thing  to  be  ac- 
complished is,  that  ship-builders  should 
be  left  free  as  possible  to  observe  those 
experiments,  learn  from  the  results  of 
them,  and  apply  that  knowledge  to  each 
successive  model.  Then  will  the  art 
of  building  be,  at  the   same  time,  the 


science  of  building  :  and  then  will  the 
interests  not  only  of  individuals,  and 
of  the  nation,  but  the  safety  and  pros- 
perity of  men,  generally,  be  promoted 
to  a  degree  not  easily  calculated. 

"  Concerning  my  views  on  sparring, 
for  which  you  inquire,  I  am  prepared 
at  present  only  to  say,  that  while  1 
have  some  views  on  that  subject  which 
I  have  never  yet  been  at  liberty  to 
carry  fully  into  practice,  I  have  not 
had  that  opportunity  for  experiment 
and  reflection  which  would  warrant 
me  in  expressing,  at  this  time,  those 
points  in  which  I  should  vary  at  all 
from  the  common  practice. 

"  With  the  best  wishes  for  the  suc- 
cess of  your  present  undertaking,  I  re- 
main, very  truly, 

"Yours, 

"DAVID  BROWN." 

The  very  first  consideration,  when 
about  making  a  model  from  which  to 
build  a  vessel,  is  the  service  for  which 
she  is  intended.  From  this  knowledge 
we  determine  the  proportionate  dimen- 
sions of  the  vessel  to  be  built.  In  the 
concluding  paragraph  of  the  first  chap- 
ter we  have  given  suitable  proportions 
for  freighting  ships  ;  circumstances, 
however,  must  govern  the  builder  in 
his  adherence  to,  or  his  departure  from 
those  proportions :  the  altitude  of  the 
load-line  of  flotation   has  also  been  de- 


MARINE    AND    NAVAL    ARCHITECTURE. 


97 


fined.  Should  it  be  necessary  to  know 
the  capacity  or  its  approximate  amount 
without  knowing  the  actual  displace- 
ment, we  maybe  able  to  determine  the 
exponent  of  capacity  of  any  part  of 
the  model  ;  and  from  this,  by  compa- 
rison with  other  models — the  en- 
tire capacity  and  exponent  of  a  cor- 
responding part  being  known — we  may 
deduce,  in  relation  to  capacity,  all  that 
may  be  necessary  for  ordinary  purposes. 
For  example,  we  will  take  the  sixth 
water-line  of  the  Ocean  Steamer,  Plate 
2  ;  length  between  the  perpendiculars, 
218  feet,  half-breadth,  18.08  feet;  these 
multiplied  together  gives  the  area  in 
square  feet  of  an  oblong  plane  (square 
at  the  ends)  with  nothing  taken  off  for 
shape  ;  we  may  now  take  the  half  area 
of  the  sixth  water-line,  which,  by  re- 
ferring to  the  tables,  we  find  to  be, 
2817.2  square  feet ;  divide  the  product 
of  the  dimensions  into  the  half  area, 
then  we  have  the  formula  as  shown  on 
page  90.  The  term  capacity  is  here 
used  in  the  same  sense  as  displacement, 
but  more  strictly  speaking,  it  pertains 
to  the  interior  part  of  the  vessel  for  the 
reception  of  cargo.  The  unit,  or  100, 
bein<>-  all  that  can  be  obtained  from  the 
square  box,  consequently,  we  have  lost 
32  per  cent.,  or  parts  of  buoyancy,  in 
providing  ;i  shape  to  answer  our  pur- 
pose at  the  sixth  water-line.  But  we 
find  that  the  whole  per  centage  of  buoy- 


ancy lost  on  this  steamer,  is  .45  per 
cent.,  or  the  exponent  of  the  entire 
capacity  is  .55  per  cent.  In  our  ex- 
positions on  the  readiest  mode  of  ma- 
king models,  we  shall  assume,  that  the 
eye  alone  is  our  text-book  with  regard 
to  form  ;  and  having  learned  what  we 
actually  do  want,  we  are  prepared  to 
make  an  effort  to  obtain  it.  The 
dimensions  of  the  ship  being  known, 
and  the  altitude  of  the  load-line  of 
flotation  above  the  base-line  also  known, 
we  may  divide  the  portion  between 
those  lines  into  equal  or  unequal  parts, 
as  occasion  may  require.  If  the  ordi- 
nary mode  is  adopted,  of  making  the 
alternate  sections  of  cedar  and  pine,  as 
in  Fig.  5,  the  lowest  piece  should  be 
of  cedar,  because  it  presents  to  the  ac- 
tion of  the  file  the  largest  surface,  and 
is  more  easily  made  fair  than  pine.  If 
the  ship  have  but  little  rise  on  the  floor, 
or  as  it  is  sometimes  expressed,  has  but 
little  dead-rise,  the  lower  piece  should 
be  the  thinnest,  on  account  of  having 
a  line  at  the  lower  part  of  the  bilge, 
which  facilitates  the  laying  off  on  the 
floor  of  the  mould  loft.  There  was  a 
time  when  builders  supposed  that  ves- 
sels must  of  necessity  draw  more  water 
aft  than  forward,  in  order  that  they 
might  obey  the  helm  readily  ;  and  the 
difference  was  often  made  to  appear  in 
the  first  water-line,  by  making  the 
lower  piece  thicker  or  deeper  aft  than 


13 


9S 


MARINE   AND    NAVAL    ARCHI  TECT  I"  R  K. 


forward,  by  as  much  as  the  required 
difference  was  assumed  to  be.  But 
this  practice  has  grown  obsolete,  and  a 
parallel  draught  of  water  is  generally 
adopted  ;  not,  however,  before  the  most 
abundant  proof  had  been  afforded,  that 
the  practice  was  without  a  basis  in  the 
principles  of  sound  philosophy.  In 
determining  the  altitudes  of  the  load- 
line  of  flotation,  it  does  not  arbitrarily 
follow,  that  the  model  shall  have  no 
parallel  pieces  above  this  line  ;  we  may 
for  convenience  insert  more  ;  the  effect 
of  which  is  to  reduce  the  thickness  of 
the  first  sheer-piece.  Nor  is  it  abso- 
lutely necessary  that  the  sheer-pieces 
should  be  alternately  of  cedar  and  pine. 
Some  reference  should  be  had  to  the 
disposition  of  the  plank  on  the  top- 
sides  of  the  ship,  if  it  is  designed  to 
have  a  projection  of  the  upper  wale 
and  thinner  plank  above,  such  as  are 
usuallv  called  strings  :  the  sheers  on  the 
model  should  correspond  with  such  ar- 
rangements, in  order  that  the  sirmarks 
m.iy  serve  as  a  guide  in  regulating  the 
sheer  on  the  ship.  It  will  be  seen  that 
the  proportions  of  deptli  for  ships,  as 
defined  on  page  43,  are  calculated  from 
base  line  to  the  lower  side  of  the 
plank-sheer,  or  as  it  is  sometimes  call- 
ed, the  covering  board  ;  and  as  a  conse- 
quence, one  sheer-line  should  be  shown 
on  the  model  at  this  height,  measured 
on  the  greatest  transverse  section.     It 


may  be  farther  remarked,  in  relation 
to  former  practices,  that  when  ships 
were  supposed  to  require  a  heavier 
draught  of  water  alt  than  forward, 
they  were  no  deeper,  when  measured, 
from  the  water-line  to  the  rail  forward, 
than  aft.  But,  as  we  before  remarked, 
all  the  difference  of  depth  was  beneath 
the  surface  of  the  water  ;  and  although 
the  practice  is  not  now  adhered  to 
among  the  prominent  builders  of  this 
country,  it  is  yet  tenaciously  guarded 
against  innovations  in  many  parts  of 
the  old  world.  The  idea  would  be  re- 
garded as  preposterous,  of  building  a 
ship  deeper  forward  than  aft  ;  but  such 
is  the  present  practice  in  New-York, 
where  it  was  first  introduced,  and  the 
results  have  proved  most  satisfactory  ; 
and  ships  have  been  built  in  this  city, 
having  from  three  to  five  feet  of  differ- 
ence in  depth  at  the  ends,  which  adds 
greatly  to  their  appearance,  as  well  as 
to  their  performance.  It  will  not  be 
denied,  that  a  ship  cannot  be  placed  in 
a  more  awkward  trim,  as  it  regards  her 
appearance,  than  to  appear  to  trim  by 
the  head  ;  this  applies  to  every  ship  of 
equal  deptli  at  the  two  ends.  But  this 
is  not  all;  the  bulkiest  part  of  the  bow 
is  brought  into  immediate  contact  with 
the  surges  of  every  wave  ;  whereas, 
had  the  same,  or  nearly  the  same,  an- 
gle of  resistance  been  continued  above 
the    load-line,    and    the    flare    of    the 


MARINE    AND    NAVAL    ARCHITECTURE, 


99 


whole  bow  been  raised  some  three  or 
four  feet,  as  the  exigencies  of  the  case 
might  have  required,  the  ship  would 
have  sailed  faster,  taken  less  water  on 
board,  and  made  better  weather,  in 
every  respect.  As  we  have  set  apart 
a  portion  of  a  subsequent  chapter,  to 
delineate  the  advantages  and  tbe  read- 

O 

iest  mode  of  sheering,  we  will  follow 
the  subject  no  farther :  one  or  more 
pieces  may  fill  the  space  between  the 
lower  side  of  the  plank-sheer  and  the 
lower  side  of  the  rail;  if  the  lower  sheer- 
piece  of  the  model  have  for  its  boun- 
dary lines  a  straight  side  below,  and  of 
any  considerable  thickness,  the  upper 
pieces  may  be  made  thin,  and  bent  into 
the  lower  sheer  ;  this  will  answer  all 
practical  purposes,  and  will  save  time, 
as  a  piece  of  parallel  thickness  and 
straight,  is  much  quicker  prepared  than 
one  of  different  thickness,  and  crooked. 
The  whole  number  of  pieces  may  be 
confined  with  dowels  running  perpen- 
dicular to  the  surface,  or  they  may  be 
screwed  together  in  layers.  As  the 
model  represents  but  half  the  ship,  as 
a  consequence,  one  side  must  present 
a  plane,  which  must  be  perfectly  fair  ; 
and  upon  this  plane,  the  plan  denomi- 
nated the  sheer-plan,  is  projected ; 
this  plan,  which  is  the  first  laid  oft", 
(whether  on  the  model,  or  on  the  floor,) 
is  bounded  by  the  base-line,  which 
is  the  top  of  tin;  keel,  by  the  rabbet  on 


the  stem,  and  likewise  on  the  stern- 
post,  which  is  usually  the  inside  of  those 
parts,  respectively  ;  the  upper  sheer  is 
regarded  as  the  lower  side  of  the  rail ; 
hence  it  follows,  that  the  sheer-plan 
determines  the  length  of  the  ship,  and 
the  heights  at  the  several  sheers  and 
water-lines,  or  parallels  to  the  line  of 
flotation.  Although  the  practice  of 
regarding  the  rabbet  as  the  inside  of  the 
stem  and  stern-post,  has  been  adhered 
to,  almost  from  time  immemorial,  yet 
it  cannot  be  shown  to  be  the  most  ju- 
dicious arrangement  that  can  be  made 
in  securing  those  important  parts  of  the 
vessel.  We  shall  give  an  exposition,  in 
its  proper  place,  of  the  utility  of  having 
the  stem  and  stern-post  inside,  instead 
of  outside  of  the  ship.  The  materials 
for  the  model  having  been  arranged  and 
secured,  either  with  screws  or  dowels ; 
and  the  plane,  representing  the  middle 
line,  made  perfectly  fair,  we  may  dress 
the  opposite  side  parallel  to  the  first 
setting  oft*  the  dimensions,  as  being 
whatever  half  the  beam  of  the  ship  re- 
quires to  be  in  feet  and  parts,  when  ap- 
plied to  the  scale  by  which  the  model 
is  made.  We  next  come  to  the  loca- 
tion and  shape  of  the  greatest  trans- 
verse section.  Much  has  been  written 
upon  this  subject,  and  there  being  still 
room  for  more,  we  shall  not  stop  the 
progress  of  the  model  to  discuss  this 
matter,  farther  than  to  tell  our  readers 


100 


MARINE    AND    NAVAL    ARCHITECTURE. 


where  we  would  place  it,  and  give  our 
reasons  for  so  doing,  after  we  have 
progressed  farther  with  the  work  before 
us.  We  hesitate  not  to  assert,  that  if 
nine  ships  out  of  every  ten  bad  their 
greatest  transverse  section  shifted  far- 
ther  aft,  and  their  centre  of  propul- 
sion made  to  correspond  with  the 
change,  that  they  would  perform  bet- 
ter than  they  now  do  ;  and  entertain- 
ing these  views,  based  upon  the  most 
reliable  evidence,  we  would,  on  the 
model  before  us,  place  this  section  or 
frame  on  the  longitudinal  centre  of  the 
load-line  of  flotation,  having  assumed 
the  ship  to  be  adapted  to  freighting 
purposes  ;  and  as  a  consequence,  would 
not  advise  more  than  from  four  to  six 
degrees  of  rise  on  the  floor,  which  is 
enough  to  give  us  a  bilge,  sufficiently 
easy  not  only  for  the  stability  of  the 
vessel,  but  to  prevent  her  from  rolling; 
as  the  motion  of  a  ship  has  less  to  do 
with  the  dimensions,  and  more  to  do 
with  the  shape,  than  the  great  bulk  of 
mechanics  and  seamen  are  willing  to 
admit ;  and  as  far  as  the  stability  of  a  ship 
is  consequent  upon  the  three  principal 
dimensions,  so  far  do  our  ship-owners, 
masters,  and  very  many  builders,  be- 
lieve the  preventatives  against  rolling 
extend,  and  no  farther.  This  is  a  con- 
tracted view  of  this  important  question, 
and  teaches  us  that  theory. and  practice 
have  never  held  intercourse  upon  a  sub- 


ject in  which  the  comfort  of  all  who 
navigate  the  ocean  is  most  intimately 
connected;  but  we  pause  not  now  to 
investigate  this  theorem,  having  an 
ideal  model  before  us. 

After  having  suited  ourselves  in  the 
shape  of  the  greatest  transverse  seo 
tion,  we  may  follow  in  the  beaten  track, 
and  work  oft' the  model  until  it  fills  the 
eye,  or  suits  our  taste,  by  first  mould- 
ing out  the  top  sheer  or  lower  side  of 
the  rail,  as  near  as  we  can  at  present 
judge  of  what  Ave  want,  subject,  how- 
ever, to  such  alterations  as  will  present 
themselves,  after  the  surplus  bulk  is  re- 
moved ;  or  we  may  pursue  the  course 
already  described  in  finding  the  expo- 
nent of  the  area  of  load-line;  and,  by 
separating  the  model,  adjust  the  form 
to  suit  our  notion,  and  the  area  to  the 
surface  we  require  ;  the  immersed  part 
of  the  model  may  be  again  united  to 
the  topsides,  or  kept  apart,  until  par- 
tially finished.  If  we  adopt  the  method 
shown  in  Fig.  4,  of  obtaining  the  ca- 
pacity or  displacement  we  require,  by 
the  hydrostatic  balance,  or  if  we  adopt 
that  of  Fig.  5,  by  comparative  weight, 
we  must  keep  the  model  free  for  sepa- 
ration at  load-line.  We  have  shown, 
in  Chapter  I.,  the  more  simple  methods 
of  obtaining  the  centre  of  gravity  of 
displacement,  as  illustrated  in  Fig.  3 ; 
and  without  a  knowledge  of  the  local- 
ity  of  this  point,  we  shall  be  unable  to 


MARINE  AND  NAVAL  ARCHITECTURE. 


101 


adjust  the  propelling  power,  with  any 
certainty  of  success,  before  the  bottom 
is  done,  we  may  connect  it  with  the 
topside,  and  make  one  part  to  suit  the 
other.  In  shaping  the  topsides,  we  should 
remember  that  although  a  flaring  bow 
causes  the  ship  to  have  a  light  and 
lively  appearance,  yet  it  should  flare 
but  little,  if  any,  as  far  aft  as  the  fore- 
mast, on  account  of  the  fore-rigging-, 
which  will  come  in  contact  with  the 
rail,  unless  the  channels  are  wide,  which 
is  always  to  be  avoided  when  practica- 
ble. Utility  has  also  adopted  the  pre- 
vailing custom  of  forming  the  topsides 
aft,  or  the  rail  with  more  round  than 
the  wale  ;  the  object  of  which  is,  that 
the  mizzen-rigging  may  be  kept  clear 
of  the  rail,  with  a  smaller  channel  than 
either  that  of  the  fore  or  main,  as  the 
breadth  and  length  of  the  channels 
should  bear  the  same  proportions  to 
each  other  that  the  masts  do,  one  to 
the  other  ;  hence  it  follows,  that  the 
mizzen-mast  being  the  shortest,  and 
the  inizzen-channel  the  narrowest,  the 
rail  would  become  the  channel,  unless 
there  was  more  round  to  the  after 
frames  on  the  head.  This  remark  will 
apply  to  all  the  top  hamper  on  the  side 
of  the  ship,  above  the  channels,  which 
can  scarcely  be  made  sufficiently  se- 
cure (without  direct  reference  is  had 
to  a  more  elevated  position  in  the  dis- 
tribution of  timber  in  the  frames)  above 


the  deck,  or  plank-sheer.  A  proper 
rake  for  the  stem' may  be  thus  defined: 
enough  above  water  to  give  life  to  the 
bow.  Below  water  there  is  no  absolute 
necessity  for  any  rake  ;  but  enough  to 
make  the  bow  below  look  as  if  it  be- 
longed to  the  same  ship  as  that  of  the 
bow  above  water,  is  not  objectionable. 
We  would  not  be  as  stringent  in  this 
matter,  as  many  theorists  have  been  in 
rearing  restrictive  bulwarks  around  the 
stem  of  a  ship  ;  by  giving  the  exact 
angle  of  its  rake,  we  believe  that  no 
definite  angle  can  be  given  that  will  ap- 
ply to  every  vessel ;  the  whole  bow  has 
something  to  do  with  its  boundary  line, 
which  the  stem  undoubtedly  is  ;  and 
we  would  add,  that  not  only  the  shape, 
but  the  strength  of  the  bow,  has  some- 
thing' to  do  with  the  rake  of  the  stem. 
A  lively  light  bow  may  be  obtained, 
with  a  very  considerable  rake  to  the 
stem.  Fifteen  degrees  is  an  abundance 
for  almost  any  description  of  vessels. 
If  we  have  a  great  rake  to  the  stem,  it 
inevitably  follows  that  we  have  a  great 
overhang  to  the  bow,  which  tends  to 
strain  and  hog  the  ship  ;  all,  or  most 
of  the  flare  we  require,  may  be  obtain- 
ed by  curving  the  knight-heads  forward, 
which  is  an  advantage  in  more  than 
one  respect;  it  not  only  adds  to  the 
lively  appearance  of  the  bow,  but  it 
sharpens  the  rail,  and  cases  the  whole 
bow  above  the  plank-sheer,  which  ma- 


102 


MARINE    AND    NAVAL    ARCHITECTURE. 


terially  relieves  the  ship  from  those 
surges,  in  ;i  heavy  head  sea,  which 
every  mariner  knows  makes  the  strong- 
est ship  vibrate  from  stem  to  stern. 
This  form  of  stem  was  introduced  by 
the  author,  and  exhibited  at  the  fair  of 
the  American  Institute  in  1S42.  It 
was  not,  however,  well  received  at  that 
time,  but  has  since  been  regarded  as  an 
improvement,  and  adopted  as  such. 
Upon  the  proper  rake  for  the  stern-post 
much  has  been  written  by  scientific 
men,  from  which  the  mechanic  might 
be  led  to  infer,  that  the  success  of  a 
ship  depended  upon  the  particular  rake 
of  the  stern-post.  This  is  not  the 
case,  the  steering  qualities  of  a  ship  are 
not  consequent  upon  the  rake  of  the 
post,  but  they  are,  to  a  very  great  ex- 
tent, upon  the  manner  in  which  it  is 
connected  with  the  ship.  l{  the  post 
be  large,  fore-and-aft,  and  is  placed  out- 
side of  a  ship  that  is  full  about  the 
load-line,  she  cannot  perform  to  the 
entire  satisfaction  of  those  who  man- 
age her.  It  will  appear  quite  manifest 
to  the  thinking  man,  that  a  ship,  or 
other  vessel,  would  steer  with  a  much 
smaller  rudder,  were  all  but  a  suffi- 
ciency of  caulking- wood  placed  inside 
of  the  vessel,  and  the  remainder  beard- 
ed off  in  the  direction  and  with  the  lines 
of  the  vessel  below  water,  as  in  Fig. 
14.  There  are  many  vessels  that  have 
a  stern-post  quite  large  enough  for  a 


rudder,  were  it  hung  on  pintles.  It 
does  not  require  as  much  rudder  as 
many  suppose  to  steer  a  ship,  if  it  be 
placed  in  the  proper  place.  And  we 
dogmatically  assert  it,  that  the  aft  edge 
of  a  large  stern-post  is  not  the  place 
for  a  rudder.  For  steering  purposes, 
the  rudder  should  be  placed  at  the  ter- 
mination of  the  lines  of  the  bottom, 
and  when  this  is  the  case  much  less 
rudder  is  required,  particularly  if  the 
vessel  have  a  fair  swell  of  all  the  lines. 
Diagram  No.  14,  exhibits  the  present 
mode  of  uniting  the  rudder  to  the  stern- 
post,  outside  of  the  ship,  contrasted 
with  that  of  connecting  the  rudder  to 
the  post,  at  the  termination  of  the 
lines,  and  the  motion  of  the  contiguous 
body  of  water  shows  at  once  which  is 
the  most  effective  mode.  The  differ- 
ence is  so  apparent,  that  a  ship  having 
a  stern-post,  as  No.  2  of  the  same  dia- 
gram, with  an  ordinary  sized  rudder, 
will  feel  her  helm  so  quick,  that  a  ma- 
jority of  good  seamen  would  pronounce 
her  a  bad  steering  ship,  while  the  only 
fault  would  be,  too  much  rudder;  and 
any  manageable  ship,  under#  the  pro- 
posed improvement,  would  not  require 
more  than  two-thirds  of  the  rudder- 
surface  that  she  otherwise  would,  un- 
der the  old  method.  And  if  the  ship 
were  modelled  in  accordance  with  the 
expositions  already  given,  viz.,  by  ma- 
king the  bow  sharper,  placing  the  great- 


MARINE    AND    NAVAL    ARCHITECTURE 


103 


est  transverse  section  at  or  aft  of  the 
longitudinal  centre,  and  filling-  out  the 
stern,  as  has  been  described,  the  ship 
would  not  require  more  than  half  the 
usual  amount  of  rudder-surface.  But 
we  must  look  farther  to  see  all  the  ad- 
vantages accruing  from  this  improve- 
ment; the  security  of  the  rudder  itself 
should  not  be  regarded  as  a  matter  of 
little  moment.  A  large  rudder,  swing- 
ing at  the  mercy  of  a  heavy  cross-sea, 
is,  at  all  times,  to  be  avoided,  even 
when  the  post  to  which  it  is  attached 
is  perfectly  secure  ;  but  when  we  con- 
sider that  the  post  itself,  to  which  the 
rudder  is  attached,  can  hardly  be  made 
secure,  in  its  isolated  position,  we  must 
at  once  yield  to  this  innovation  into 
the  stereotyped  practice  of  our  sires. 
And  the  very  fact  of  ships  having  had 
their  stern-posts  started  from  their 
place,  is  sufficient  to  convince  us  that 
any  measure  that  will  render  the  post 
secure,  and  reduce  the  size  of  the  rud- 
der, must  be  regarded  as  an  improve- 
ment, and  should  be  at  once  adopted, 
for  the  better  security  of  human  life, 
in  confiding  passengers,  and  those 
whose  home  is  on  the  deep. 

We  are  aware  that  this  does  not  ac- 
cord with  the  cherished  opinions  of  the 
commercial  world  ;  but  we  have  fairly 
examined  and  proved  this  problem,  and 
therefore  risk  nothing  in  giving  it  pub- 
licity.    We   wish,  however,  to  be  dis- 


tinctly understood,  that  we  do  not 
mean,  when  we  recommend  a  fullness 
aft,  that  irregular  sicell  in  the  load- 
line,  under  the  quarter,  and  a  large 
skeig  below ;  neither  do  we  mean  a 
fullness  below  water,  by  carrying  the  flat 
of  the  floor  almost  to  the  stern-post  ; 
but  we  mean  a  regular  swell  on  all  the 
lines  below  water.,  and  the  removal  of 
the  cumbrous  buttocks  that  cause  ves- 
sels to  carry  a  weather-helm,  by  making 
so  great  a  contrast  in  the  weather  and 
lee-lines  of  flotation.  The  full  but- 
tocks that  are  adhered  to  by  the  build- 
ers, with  so  much  tenacity,  are  a  great 
detriment  to  the  ship  in  many  respects, 
and  no  advantage  in  any ;  for,  on  the 
most  feasible  grounds  that  can  be  ad- 
duced, viz.,  stability  and  beauty,  its 
disadvantages  are  but  too  visible,  and 
the  causes  for  their  removal  fairly  gain 
the  ascendancy.  If  stability  be  the  ob- 
ject in  view,  we  defeat  our  own  pur- 
pose, for  the  reason,  that  no  vessel  can 
be  stablethat  hasan  insufficiency  of  beam 
midships  ;  and  however  much  may  be 
added  to  the  ends,  at  or  above  the  sur- 
face, that  addition  of  buoyancy  defeats 
the  very  object  it  was  designed  to  ac- 
complish. When  at  rest  the  ship  is 
more  stable,  we  admit,  but  when  she 
is  pressed  forward,  whether  propelled 
by  canvass  or  steam,  the  positive  resist- 
ance along  the  bow,  and  the  negative 
resistance  on  the  quarter,  cause  a  de- 


104 


M  AIM  N  E    A  N  D    N  A  V  A  I,    A  If  C  H  I  T  E  CTDRE. 


pression  midships,  which  makes  the  ves- 
sel roll,  because  of  too  much  buoyancy 
at  the  ends  ;  whereas,  had  the  ship  an 
easier  bow,  and  the  irregular  fullness  re- 
moved from  under  the  quarter,  even 
with  the  same  principal  dimensions,  she 
would  have  been  steadier.  But  let  the 
fullness  betaken  off  the  bow  and  quar- 
ter, and  added  to  the  breadth,  midships, 
and  the  ship  will  steer  easier,  sail  faster, 
and  carry  the  same  amount  of  cargo. 
One  of  the  principal  objections  to  this 
increase  of  breadth,  is,  that  it  makes  a 
ship  roll.  This  opinion  is  without  a 
foundation  in  practical  stability  or 
sound  philosophy,  and  we  think  it  never 
would  have  been  entertained  by  prac- 
tical men,  but  for  the  invitation  to 
evade  the  tonnage  laws,  by  building 
narrow  ships.  It  is  a  great  mistake  to 
identify  the  rolling  of  a  ship  wholly 
with  the  principal  dimensions,  (as  we 
shall  show  in  its  appropriate  place.) 
Another  reason  assigned  for  a  full 
quarter,  and  a  straight  transom,  is  the 
appearance  of  the  ship,  or  that  it  is  an 
addition  to  her  beauty,  we  do  not  so  un- 
derstand the  import  of  the  term  beauty. 
We  can  give  no  other  definition  than 
the  following  :  fitness  for  the  ])urpose, 
and  proportion  to  effect  the  object  de- 
signed. The  eye  becomes  familiarized 
with  a  certain  shape,  and  habit  causes 
us  to  think  that  the  best  Ave  know  the 
most  about.      The  good  steering  quali- 


ties of  a  ship  is  an  item  worth  attend- 
ing to,  and  is  consequent  upon  the 
shape  of  both  ends  of  the  vessel.  This 
we  are  aware  is  presenting  the  subject 
under  a  different  aspect.  To  the  after 
end  of  the  ship  has  always  been  assign- 
ed the  duty  of  regulating  her  steering 
qualities.  However  new  the  dogma, 
and  however  much  it  may  conflict  with 
the  preconceived  notions  or  prejudices 
of  the  age,  the  diligent  inquirer  after 
truth  will  find  that  resistance  is  a  dis- 
turbance of  the  fluid;  and  that  the 
vessel  having  the  most  resistance,  cre- 
ates the  greatest  disturbance  of  the 
fluid.  This,  doubtless,  is  a  conceded 
point,  from  what  has  been  shown  in  a 
former  chapter,  viz.,  that  the  ship  will 
draw  more  water,  when  the  water  is  in 
a  disturbed  state,  than  when  at  rest. 
It  follows,  that  the  ship,  passing  the 
water  to  the  rudder  with  the  least  dis- 
turbance, will  steer  with  the  smallest 
rudder.  This  will  also  be  conceded  ; 
and  having  yielded  those  two  points, 
the  third  inevitably  follows,  that  the  bow 
has  quite  as  much  to  do  with  disturb- 
ing the  fluid  as  the  after  part  of  the 
bottom  ;  and  that  the  stern  should  be 
adopted  to  the  bow,  and  the  bow  to 
the  stern,  not  by  making  the  stern  full, 
because  the  bow  is  full ;  or  by  making 
the  stern  lean,  because  the  bow  is 
sharp  ;  but  by  observing  the  action  of 
the  element,  and   learning   from  what 


MARTNE  AND  NAVAL  ARCHITECTURE. 


105 


nature  and  experience  teach  us,  as  well 
;is  theory  and  practice,  both  testifying 
in  this  matter,  our  reasoning  will  be 
conclusive. 

It  has  been  set  down  as  a  truism, 
that  a  full  bow  and  a  lean  after-end 
were  the  best  for  speed,  and  every  other 
good  quality.  We  will  not  undertake 
to  say  this  is  not  true  ;  but  we  do  say, 
that  it  needs  qualifying  ;  and  we  will 
also  say,  that  the  reverse  is  equally 
true.  First,  that  it  requires  a  longer 
after-end  to  equilibriate  the  fluid,  when 
greatly  disturbed,  than  when  less,  is 
quite  apparent ;  and  the  short  bow  is 
undoubtedly  the  full  one,  and  the  long 
after- body  is  also  the  lean  one. — 
But  while  this  is  partially  true,  it  is 
strictly  so,  that  a  long  bow,  or  a  sharp 
bow,  will  perform  in  every  respect, 
better  with  a  proportionately  short 
after-end,  because  the  shape  of  the 
short  after-end  is  better  adapted  to  the 
restoration  of  the  fluid,  when  less  dis- 
turbed. And  it  is  at  once  apparent, 
that  the  long  bow  is  sharper  than  the 
short  one  ;  and,  if  properly  formed, 
disturbs  the  water  less  at  a  given 
speed,  or  has  less  resistance  at  the  same 
speed.  It  must  be  evident  to  the  think- 
ing-man, that  a  given  amount  of  power, 
when  applied  to  propel  vessels,  will 
counteract  an  amount  of  resistance 
equivalent  to  that  power  ;  and  that  as 
the  resistance  is  diminished  the  speed 


is  increased  with  the  same  power.  But 
the  shape  of  the  ship  not  only  governs 
her  speed,  her  capacity,  and  her  theo- 
retical stability,  but  it  governs  her  prac- 
tical stability.  This  problem,  in  the 
science  of  building  ships,  has  been  left 
to  theorists  for  solution,  who  have  com- 
mitted an  error  that  has  proved  fatal 
to  the  commercial  world.  By  an  in- 
genious mode  of  reasoning  they  have, 
upon  false  premises,  drawn  absurd  con- 
clusions ;  and  mankind,  ever  ready  to 
believe  that  which  their  interest  leads 
them  to  desire,  adhered  to  the  dogma, 
without  having  even  claimed  the  right 
of  thinking  for  themselves.  After  hav- 
ing  determined  the  dimensions  of  a 
ship,  without  reference  to  her  practical 
stability,  or  her  rolling  properties,  but 
with  a  view  to  her  power  to  maintain 
an  upright  position  under  a  press  of 
sail  in  smooth  water,  which  may  be 
denominated  theoretical  stability,  the 
index  of  which  is  found  in  the  altitude! 
of  the  centre  of  effort,  as  we  have  al- 
ready shown,  we  should  then  depend 
upon  the  shape  for  the  motion  at  sea, 
in  connection  with  the  proper  distribu- 
tion of  the  weights,  which  have  much  to 
do  with  the  easy  or  uneasy  motions  of 
vessels.  Two  ships  of  the  same  prin- 
cipal dimensions,  may,  when  at  rest, 
have  an  equal  amount  of  practical  sta- 
bility ;  but  when  at  sea  there  will  be  a 
wide  difference  in  the  amount;  not  only 


14 


]06 


MARINE    AND    NAVAL    ARCHITECTURE, 


so,  but  the  same  ship  may  be  so  altered 
as  to  have  her  calculated  stability  de- 
creased, and  practical  stability  increas- 
ed, as  we  base  shown  by  reducing  the 
fullness  forward,  and  of  decreasing-  the 
practical  stability,  by  making  a  full  bow 
and  a  straight  side  to  the  ship,  as  we 
have  also  shown  ;  or  in  another  way,  by 
keeping  the  extreme  breadth  below  the 
surface  of  the  water,  as  is  often  done 
to  evade  the  tonnage  laws.  The  whole 
problem  of  practical  stability  is  found 
to  be  embodied  in  this  truth,  that  the 
motions  of  ships  at  sea  are  consequent 
upon,  first,  the  altitude  of  the  centre 
of  effort,  and,  second,  upon  the  sta- 
bility of  the  centre  of  gravity  ;  hence 
it  will  appear  quite  manifest,  that  if  the 
centre  of  gravity  has  a  vertical  motion, 
it  is  not  consequent  upon  the  principal 
dimensions;  for  if  it  were,  homogeneous 
floating  bodies,  in  shape  as  well  as  in 
density,  would  also  have  a  vertical  mo- 
tion to  their  centres  of  gravity,  which 
we  know  is  not  the  case.  For  exam- 
ple, take  a  floating  body  in  the  form  of 
a  segar,  cut  it  in  two  lengthwise,  and 
it  will  be  found,  that  although  its  centre 
of  gravity  is  high,  yet  it  is  the  stiffest 
shape  that  can  be  obtained  withthe  same 
dimensions  and  area  of  surface.  Take 
a  smaller  proportion  of  depth,  which  is 
the  same  as  increasing  the  beam  or  the 
width,  and  the  results  are  the  same. 
We  do  not  adduce  this  experiment  to 


tangibly  settle  any  question  in  relation 
to  stability,  believing  with  the  author 
of  the  letter  found  in  this  chapter,  that 
the  place  for  experimenting  is  the 
ocean.  But  we  have  usvd  it  as  a  figure 
to  illustrate  a  principle  that  we  feel  safe 
in  affirming,  having  ocular  demonstra- 
tion at  hand  to  establish  it  on  a  larger 
scale.  The  steam-ship  Georgia,  doubt- 
less the  widest  ship  of  her  class  (except 
the  iron  ship  Great  Britain)  in  the 
world,  is  one  of  the  most  easy  vessels 
in  her  motions  that  floats,  notwithstand- 
ing public  opinion  had  marked  her  as 
an  unmanageable  ship,  on  account  of 
her  being  three  feet  wider  than  another 
ship  of  the  same  line,  the  Ohio,  and 
wider  than  cither  of  Collins'  line  of 
steamers,  which  are  much  larger  than 
the  Georgia.  The  Cunard  steamers 
are  also  much  narrower,  although 
longer  and  deeper.  The  America  and 
Europa  have  but  thirty-eight  feet  of 
moulded  beam,  and  the  Canada  thirty- 
nine  and  a  half  feet,  while  the  com- 
plexion of  the  practical  stability  of 
those  ships  is  so  well  known  that  we 
need  not  enlarge  upon  their  perform- 
ing qualities.  In  this  particular  it  may 
suffice  to  add,  that  the  Georgia,  with 
ten  feet  more  beam,  has  more  practical 
stability  than  any  European  steamer 
that  has  ever  entered  American  ports. 
We  have  made  our  comparisons  from 
steam-ships,  because  they  are  less  vari- 


MARINE    AND    NAVAL    ARCHITECTURE. 


107 


able  in  the  altitude  of  their  line  of  flo- 
tation ;  and  because  the  two  extremes 
were  more  fully  represented  in  this 
class  of  vessels,  than  in  freighting  or 
sailing  ships ;  consequently,  more  in- 
formation of  a  tangible  nature  may  be 
obtained.  No  two  sailing  ships  have 
ever  been  built,  about  the  same  length 
and  depth,  with  ten  feet  of  difference 
in  their  breadth,  or  at  least  we  have 
never  heard  of  so  great  a  difference  ; 
but  although  this  wholesale  experiment 
is  practical  stability,  or  the  compara- 
tive rolling  qualities  of  wide  and  nar- 
row ships,  has  settled  this  vexed  ques- 
tion, and  solved  the  problem  of  pro- 
portionate dimensions  with  regard  to 
this  important  quality  in  their  perform- 
ance, yet  the  author  would  not  stop 
here,  but  take  higher  ground,  and  as- 
sert, that  ships  may  be  built  so  long 
and  so  wide  that  the  motion  of  the  sea 
will  not  be  felt ;  in  other  words,  that 
they  will  neither  roll  nor  pitch.  We 
are  aware,  of  the  assumption,  that  in 
the  oscillating  motion  of  a  wide  ship, 
the  gunwale  or  side  rises  higher  on 
the  windward,  and  falls  lower  on  the 
leeward  side,  than  in  a  narrow  ship  ; 
but  is  it  not  equally  clear  that  there  is 
the  same  amount  of  buoyancy  on  the 
lee  as  on  the  windward  side  \  and  hence 
it  follows,  that  there  is  as  much  power 
exerted  to  resist  the  tendency  to  incli- 
nation  to  the  leeward,  as  there  is  to 


cause  the  vessel  to  incline  from  the 
windward  side.  A  steam-boat,  with 
guards  extending  beyond  the  side, would 
be  subject  to  a  greater  elevation  on  one 
side,  and  depression  on  the  other,  at 
the  extreme  breadth  of  the  guard,  with 
the  same  angle  of  inclination  as  an- 
other boat  of  the  same  breadth,  and 
having  no  guards.  This  is  quite  clear, 
but  were  the  boat  itself  built  as  wide 
as  the  guards,  the  case  would  be  quite 
different.  We  have  extended  our  re- 
marks farther  than  we  otherwise  should 
have  done,  but  for  the  discrepancy  that 
exists  between  theory  and  practice,  on 
this  particular  point.  Scientific  men 
have  been  led  into  a  fatal  error  in  their 
efforts  to  show  from  theory  the  advan- 
tages narrow  ships  possess  in  practical 
stability  ;  their  mistake  arises  from  their 
ignorance  of  the  intimate  relation  be- 
tween shape  and  the  oscillating  motion 
of  vessels. 

Commander  Fishbourne,  of  the  Royal 
Navy,  in  a  course  of  lectures  before  the 
United  Service  Institution,  in  1846,  la- 
bored to  establish  in  theory  that  which 
the  whole  commercial  world  has,  to  the 
present  time,  failed  to  prove  by  prac- 
tice, in  relation  to  the  cause  of  trans- 
verse oscillatory  motion  in  vessels  at 
sea.  This  officer,  evidently  a  man  of 
science,  makes  his  theorems  appear 
quite  plausible  to  the  casual  observer, 
w  ho  has  not  considered  that  the  ground- 


108 


MARINE    AND    NAVAL    A  K  CHIT  E  C  T  U  li  K 


work  of  his  theory  is  based  on  compa- 
risons drawn  from  sailing-vessels,  sub- 
ject to  a  number  of  contingent  circum- 
stances which  meet  him  at  every  stage 
of  advancement,  and  which  have  not 
been  brought  into  the  account,  either 
of  which  at  once  thwarts  his  path  so 
completely  as  to  obstruct  his  farther 
progress.  He  takes  it  for  granted,  that 
because  vessels  having  a  good  degree 
of  dead-rise,  are  generally  wide,  and  as 
a  consequence,  have  great  inequality 
in  the  half  area  of  the  two  lines  of 
flotation — the  windward  and  the  lee- 
ward lines — it  must  follow,  that  their 
motions  are  uneasy;  and  because  such 
shaped  vessels  require  ballast,  in  con- 
sequence of  the  centre  of  gravity  be- 
ing high,  their  practical  stability  is  thus 
reduced,  and  their  inclination  to  roll 
greatly  increased  :  but  in  the  same  sen- 
tence of  his  lecture  he  adds,  that  great 
stability  prevents  rolling.  There  is, 
doubtless,  not  a  practical  ship-builder, 
having  had  any  amount  of  experience, 
who  does  not  know,  that  a  vessel  with  an 
increasing  breadth  above  the  light-line 
of  flotation,  and  proportionately  narrow 
near  the  base,  is  stifter,  or  has  more 
stability  when  immersed  to  the  load- 
line  of  flotation,  than  another  vessel 
having  the  same  principal  dimensions, 
with  an  increased  amount  of  buoyancy 
at  the  base,  and  proportionately  less  at 
the  surface  of  the  water,  or  at  the  line 


of  flotation.     It   must  be  quite  appa- 
rent to  the  thinking-man,  that  although 
the   former  vessel   required    ballast    to 
bring  her  down  to  her  bearings,  in  con- 
sequence of  her  having  less  breadth  at 
the  light  than  at  the  load-line  of  flo- 
tation,   yet,  as    her   breadth   increased 
faster  than   the   draught  of  water  in- 
creased, her  stability  must  of  necessity 
increase   in   the    same   ratio  ;   and  far- 
ther, that  all  efforts  to  incline  such  a 
vessel  from   the   erect   position,   must 
raise  the  centre  of  gravity  like  a  clock 
pendulum,  from  its  lowest  position  ;  and 
this  resistance  to  inclination  is  greater 
in  such  shape  than  in  any  other,  when 
the  vessel  is  loaded,  and  less  when  light; 
whereas,  the  vessel  with  a  hard  bilge, 
long  floor  transversely,  a   plumb   side, 
and  having  the  same   amount  of  dis- 
placement, with   less  breadth,   will   be 
stifler  than  the  other,  when  light,  and 
less  so  when  loaded  ;   and  the  reasons 
are  obvious,  the   fullness  below  when 
light  furnishes  a  sufficiency  of  area  to 
sustain   the    topside ;     but    when    this 
broad  base  is  depressed  by  cargo  to  the 
loaded  depth,  at  every  inclination,  how- 
ever small,  the  efforts  to  trip  the  ves- 
sel are  manifest,  and  the  ship  rolls  un- 
til the  influence  of  the  centre  of  gra- 
vity, in  its  ascent,  counterbalances  the 
extra    buoyancy,     and     she     is    again 
brought  back  not  only  to  the  erect  po- 
sition, but   beyond    it,    when   the  same 


MARINE    AND    NAVAL    ARCHITECTURE, 


109 


freak  is  performed  on  the  other  side. 
While  the  vessel  is  at  rest  and  upright, 
all  is  well,  because  the  centre  of  gravity 
and  the  centre  of  buoyancy  are  in  a  ver- 
tical line,  and  the  one  directly  operates 
on  the  other ;  but  at  the  least  inclina- 
tion the  influence  is  lost,  and  each  cen- 
tral point  has  a  separate  interest  to 
attend  to.  The  operation  is  the  same 
as  with  a  man  in  the  water,  who  would 
venture  to  place  a  bladder  under  his 
feet ;  it  is  evident,  that  while  he  kept 
himself  erect,  he  would  have  a  suffi- 
ciency of  buoyancy  to  keep  his  head 
above  water,  but  let  his  feet  incline 
either  way,  and  it  would  be  impossible 
to  maintain  an  equilibrium,  for  the  very 
reason  that  he  had  too  much  buoyancy 
at  the  base,  and  too  little  at  the  line  of 
flotation  ;  but  let  him  extend  his  arms, 
and  hold  a  bladder  in  each  hand,  and 
he  can  maintain  the  erect  position. 
Why?  because  he  has  a  greater  propor- 
tion of  buoyancy  at  the  surface,  or  at 
the  line  of  flotation,  than  at  the  base. 
Upon  this  hypothesis  the  reason  is  quite 
manifest,  why  the  steam-ship  Georgia 
should  roll  less  than  other  ships  of  her 
class,  with  ten  feet  more  beam  :  and 
upon  no  other  terms  will  theory  and 
practice  agree  to  assist  each  other  in 
the  demonstration  of  truth. 

The  stability  of  a  ship  does  not  de- 
pend upon  the  altitude  of  the  cent  re  of 
gravity,  but  upon  the  distance  between 


the  centre  of  gravity  and  the  centre  of 
displacement,  and  the  shape  determines 
to  a  very  great  extent  that  distance.  A 
ship  that  has  an  easy  bilge,  with  four  or 
five  degrees  of  rise  to  her  floor,  and  the 
flat  perfectly  straight,  from  the  keel 
outward,  with  a  good  breadth  of  beam, 
the  extent  of  which  is  at  the  load-line 
of  flotation,  will  roll  but  little,  and  her 
roll  will  be  easy  and  regular.  In  Fig. 
15  will  be  found  one  of  Commander 
Fishbourne's  diagrams,  by  which  he  il- 
lustrates the  action  of  the  sea  when 
ships  are  thrown  upon  their  beam-ends. 
When  passing  up  the  face  of  the  wave, 
the  ship  has  to  pass  through  an  enor- 
mous arch  before  she  arrives  perpen- 
dicular to  the  other  face  of  the  wave, 
as  from  one  to  two,  or  from  three  to 
four,  suddenly  ;  the  momentum  is  so 
great,  that  unless  a  vessel  has  a  good 
breadth,  or  a  good  degree  of  stability, 
she  is  apt  to  lose  her  equilibrium,  and 
fall  over ;  and  it  is  somewhat  surpris- 
ing that  he  should,  under  such  circum- 
stances,  repudiate  breadth.  But  we 
need  not  leave  the  mechanical  world 
to  find  absurdities  ;  men  whose  obser- 
vation should  have  led  them  to  a  tangi- 
ble basis  upon  subjects  of  so  much  mo- 
ment to  the  mechanical  and  commer- 
cial interests  with  which  they  are  im- 
mediately connected,  are  found  adhe- 
ring to  opinions  which  have  no  basis  in 
philosophy  or  experience  ;  and  adhere 


1]0 


MARINE    AND    NAVAL    ARCHITECTURE. 


to  those  opinions  with  an  astonishing 
degree   of  tenacity,  being  able  to  give 

no  hotter  reasons  for  their  opinions 
than  because  it  is  so ,  or public  opinion 
so  recognizes  it,  and  it  must  be  so. 

We  deem  it  unnecessary  to  pursue 
this  subject  farther  at  this  stage  of  the 
work,  but  shall  continue  to  fortify  our 
position  with  tangible  demonstrations 
from  the  several  descriptions  of  vessels 
that  may  be  found  in  the  work.  We 
shall  again  resume  the  making  of  a 
model,  and  pursue  the  work  to  its  com- 
pletion. The  advantages  of  having  tlie 
stern-post  inside  rather  than  outside  of 
a  ship,  having  been  shown,  we  will 
next  make  an  effort  to  exhibit  the  ad- 
vantages of  having  the  stem  inside,  or 
at  least  enough  to  enable  us  to  beard 
it  off  in  the  direction  of  all  the  lines 
below  water,  not  so  much  from  the 
danger  of  having  it  started  from  its 
socket,  (as  the  stern-post  sometimes 
is,)  but  in  consequence  of  the  im- 
pression it  makes  in  entering  the 
water,  which  is  of  some  moment  in 
any  description  of  vessel.  This  we  are 
aware  cannot  well  be  accomplished 
without  making  the  siding  size  of  the 
stem  larger  from  the  base  upward, 
which  should  be  done,  whether  the  sug- 
gested improvement  takes  place  or  not, 
the  cutwater  should  have  a  firm  basis 
and  when  thus  supported  is  doubly 
secure,  not  only  in  consequence  of  the 


• 


back  having  a  broad  surface  against 
the  stem,  but  by  spreading  the  fasten- 
ing we  add  strength  and  security;  and 
every  ship's  stem  should  be  sided  larger 
at  the  head  than  the  siding  size  of  the 
keel,  and  this  applies  equally  well  to  the 
stern-post;  and  some  builders  carry  out 
this  improvement,  by  making  the  post 
larger  at  the  head  than  at  the  keel ;  the 
advantages  are  at  onee  apparent,  if  we 
consider  the  post  as  it  is  now  placed, 
outside  of  the  ship,  requiring  more 
support  than  it  can  possibly  receive, 
apart  from  the  advantage  of  obtaining 
a  large  rudder-stock,  without  material- 
ly weakening  the  post,  as  well  as  fur- 
nishing a  more  firm  basis  on  the  dead- 
wood  and  transoms.  The  rake  of  the 
stern  demands  notice.  No  rule  should 
be  laid  down  as  an  invariable  oik;  for  ra- 
king the  stern  of  a  ship ;  twenty-five  de- 
grees from  a  vertical  line,  or  from  a  line 
perpendicular  to  the  base,  is  enough  in 
any  case  for  all  practical  purposes  ;  the 
starting  point,  or  the  base  of  the  stern, 
is  the  transom  or  cross-seam,  when 
we  have  no  transom,  and  the  whole 
of  this  important  appendage  to  the 
ship, — which  has  for  ages  perplexed 
and  pleased  the  mechanical  world, — 
will  then  rest  upon  this  boundary  line. 
Hence  the  importance  of  first  defining 
its  limits.  The  cross-seam  derives  its 
name  from  the  ending  of  the  diago- 
nal and  sectional  lines  on  this  line  or 


MARINE   AND    NAVAL    ARCHITECTURE. 


Ill 


seam,  where  all  the  planks  of  the  bottom 
which  come  within  its  limits  terminate, 
and  are  met  by  planks  running  horizon- 
tal, and  denominated  the  counter.  Its 
proper  altitude  has  not  been  defined  by 
ship-builders  themselves.  It  has  been 
almost  a  universal  practice  to  allow  a 
counter  broad  enough  at  an  angle  of 
about  twenty-five  to  twenty-eight  de- 
grees from  a  horizontal  line,  to  cover 
the  rudder  with  a  strake  of  from  five  to 
six  inches  wide,  upon  which  the  arch- 
board  is  based,  at  an  angle  of  about  forty 
degrees  from  a  horizontal  line.  The 
width  of  this,  in  some  degree,  depends 
upon  the  size  of  the  ship,  and  upon  the 
taste  of  the  builder;  the  .usual  width 
will  come  within  from  twelve  to  fifteen 
inches,  and  above  this  the  stern  is  pro- 
jected. The  continued  practice  of 
forming  cabin-windows  immediately  un- 
der the  deck-beams,  and  above  the  arch- 
board,  has  kept  the  cross-seam  below 
its  proper  place  ;  but  in  many  instan- 
ces, where  the  upper-deck  does  not  ex- 
tend aft,  and  the  stern  having  false  lights, 
or  round  ones,  the  arch-board  might  be 
raised,  and  as  a  consequence,  the  cross- 
seam  would  follow,  and  we  thus  would 
be  enabled  to  effectually  relieve  the 
ship  of  those  cumbrous  buttocks  that 
are  the  immediate  cause  of  the  weather- 
helm,  by  creating  inequality  in  the  in- 
clined lines  of  flotation.  There  is,  how- 
ever, another  objection  to  raising  the 


cross-seam,  particularly  at  the  quarter, 
made  by  ship-builders,  which  is  equally 
groundless  ;  were  the  quarter  eased  at 
the  usual  termination  of  the  quarter- 
piece,  the  upper  wale  would  lose  its  pro- 
minent features,  by  being  twisted  under 
the  quarter.  We  are  disposed  to  meet 
prejudice  at  every  turn,  or  we  would 
not  have  noticed  this  objection.  It 
would  scarcely  seem  possible  that  me- 
chanics could  be  found  in  this  a^e  that 
would  adhere  in  practice  to  what  their 
judgment  and  experience  condemned, 
because  habit  had  made  it  appear  less 
objectionable.  We  have  already  given 
a  definition  of  beauty,  which  we  think 
cannot  be  controverted.  The  last  ob- 
jection may  be  easily  removed,  by  hav- 
ing no  projection  to  the  wale  ;  and  any 
vessel  is  better  without  the  projection 
than  with  it.  A  flush  side  is  least  apt 
to  get  marred,  and  the  ship  is  equally 
as  strong  :  one  or  more  colored  strakes 
may  be  run  by  the  seam,  which  should 
be  quite  as  fair  as  though  there  was  a 
projection.  Before  concluding  our  re- 
marks on  the  stern,  as  defined  by  the 
model,  we  would  add,  that  life  and  zest 
are  imparted  to  the  stern  of  vessels  by 
raking  them  more  at  the  quarter,  and 
less  at  the  centre,  than  builders  usually 
do ;  and  to  the  objections  that  may, 
and  doubtless  will  be  raised,  viz.,  that 
the  stern  is  not  so  strong,  and  that  it  is 
more  expensive,  as  the  twist  compels 


112 


MARINE    AND    NAVAL    ARCHITECTURE 


them  to  use  narrower  plank  than  they 
now  do;  we,  in  reply,  first,  as  to  the 
strength — the  stern  is  stronger  than  the 
present  mode,  because  it  would  rake 
less  at  the  centre  than  they  now  do ; 
: 1 1 1 <  1  no  one  will  have  the  hardihood  to 
say  that  a  great  rake  does  not  diminish 
the  strength  of  the  stern.  But  with 
regard  to  the  strongest  manner  of 
building  sterns,  we  think  we  shall  be 
able  to  show,  in  its  proper  place,  that 
the  present  mode  of  building  sterns  is 
not  only  less  strong,  but  more  expensive 
than  another  that  has  been  introduced. 
In  answer  to  the  second  objection  to  a 
twisting  stern  on  account  of  the  plank- 
ing, we  may  remark,  that  by  covering 
the  stern  with  wide  plank,  we  are  com- 
pelled to  line  or  sheath  it, — which 
causes  it  to  rot  sooner  than  it  would 
were  it  exposed  to  the  air ;  the  wide 
plank  on  the  stern  shrinks,  and  the 
scams  become  open,  which  cannot  be 
caulked  without  marring  the  stern. 
With  those  general  observations  we 
will  leave  this  part  of  the  ship,  and  fur- 
nish some  other  general  rules  for  the 
young  beginner,  in  making  models. 
While  we  adhere  to  the  practice  of 
determining  by  the  eye  the  proper 
shape  for  vessels,  the  beginner,  or  the 
inexperienced  mechanic,  will  find  it  to 
his  advantage  to  put  his  model  together 
with  reference  to  more  than  one  set  of 
lines ;  by  doing  this  he  will  be  able  to 


discover  new  principles  in  modelling 
which  he  never  thought  of.  and  which, 
perhaps,  never  would  have  been  brought 
to  bear  upon  modelling  vessels,  without 
similar  aid.  Fig.  16  shows  three  modes 
of  putting  models  together  that  will  ex- 
hibit the  manner  and  direction  in  which  I 
the  resistance  to  motion  is  met  on  ves- 
sels ;  and  while  we  may  be  able  to  ob- 
tain  the  tables  for  the  loft,  from  a  mo- 
del thus  put  together,  we  may  also  im- 
prove our  judgment  in  filling  the  eye, 
before  we  become  so  completely  famili- 
arized with  a  certain  shape  from  which 
we  cannot  depart.  It  will  be  found, 
by  a  strict  inquiry  into  the  various 
opinions  of  those  who  model  vessels, 
that  there  is  very  little  originality  of 
opinion  with  regard  to  shape ;  what 
is  often  termed  experience,  is  rarely 
more  than  hereditary  notions,  handed 
down  from  father  to  son  ;  and  if  the 
young  man  dare  to  form  opinions  from 
his  own  observation,  which  conflict 
with  those  of  his  sire,  he  is  but  too 
often  branded  as  an  addle-pated  enthu- 
siast, or  a  reckless  adventurer  upon  the 
ocean  of  fame.  When  we  say  there  is 
but  little  originality  in  modelling,  we 
mean,  in  general  terms,  or  compara- 
tively so;  for  while  in  this,  as  in  no 
other  branch  of  mechanism,  every  per- 
son has  formed  an  opinion  of  the  re- 
quisite qualities  vessels  should  possess, 
few,  indeed,  have  based  those  opinions 


MARINE    AND    NAVAL    ARCHITECTURE. 


113 


independent  of  any  expression  from 
others.  We  have  said,  in  a  former 
chapter,  that  shape  in  ships  is  as  dis- 
tinctly traceable  to  the  builder  as  linea- 
ments are  in  the  human  face  ;  hence 
the  importance  of  looking  well  to  this 
matter,  before  we  are  trammeled  with 
a  shape  from  which  we  cannot  depart, 
even  though  we  may  be  convinced  of 
error. 

The  diagram,  No.  1,  of  Fig.  16,  re- 
ferred to,  exhibits  the  greatest  trans- 
verse section  of  a  vessel.  The  bound- 
ary lines  are,  the  middle  line,  the  shape 
of  the  frame,  and  a  horizontal  line 
meeting  the  two  former  at  the  lower 
side  of  the  plank-sheer  ;  the  load-line  is 
a  proportionate  distance,  and  the  lines 
below  the  load-line  are  so  arranged 
that  the  direction  of  the  forces  are 
very  nearly  represented  ;  the  lines  run- 
ning from  the  middle  line,  and  pointing 
downward,  are  an  approximation  to 
what  are  recognized  as  diagonal  lines, 
and  show  nearly  in  the  direction  of  the 
plank  on  the  bottom  ;  but  they  repre- 
sent something  on  the  model  of  more 
importance  ;  they  approximate  the  di- 
rection of  the  rotary  motion  of  the 
molecules,  of  which  the  fluid  is  com- 
posed— the  lines  varying  from  the  verti- 
cal, or  middle  line,  as  we  recede  from  the 
centre — and  exhibit  the  direction  of  the 
pressure  at  different  parts  of  the  bot- 
tom of  the  ship  ;   for  example,  the  di- 


rection of  the  pressure  at  the  stem  and 
stern-post,  is  at  right-angles  with  the 
middle  line,  or  parallel  to  the  horizon  ; 
but  as  we  recede  from  those  points,  or 
move  aft  from  the  stem,  and  forward 
from  the  post,  the  direction  of  the 
pressure  is  found  to  be  at  right-angles 
with  the  first  line,  numbering  from  the 
middle  line.  As  we  advance  still  farther 
towards  the  centre  of  the  ship,  we  find 
the  direction  to  be  perpendicular  to  the 
second  line ;  we  still  progress  in  our 
advances  toward  the  centre,  and  the 
third  line  furnishes  the  same  results  as 
the  former  ;  the  fourth  answers  a  like 
purpose:  those  lines  are  but  an  approxi- 
mation to  the  direction  of  those  forces, 
as  it  is  evident  that  nothing  more  could 
be  given  in  advance,  as  the  model,  we 
must  remember,  is  not  yet  made.  In 
dressing  the  materials  for  a  model  of 
this  description,  we  must  bring  all  the 
stuff  to  a  parallel  width,  which  will 
bring  all  the  pieces  the  same  distance 
from  the  middle  line,  and  from  the  base- 
line at  each  end  ;  it  will  be  discovered 
that  No.  1  also  forms,  by  the  intersect- 
ing points,  parallels  to  the  line  of  flota- 
tion, or  water-lines.  The  materials,  or 
pieces,  should  be  alternately  of  differ- 
ent colors,  as  shown  in  the  diagram. 
No.  2  exhibits  another  mode  of  putting 
models  together  for  instruction;  and  as 
the  water-line,  or  the  parallel  to  the 
line  of  flotation,  can  liardly  be  dispensed 


15 


Ill 


MARINE   AND    NAVAL    A  R  C  H  I  T  E  CTI   RE. 


with  at  fust,  we  might  find  it  an  ad- 
vantage to  make  twin  models,  or  both 
sides  of  the  ship,  adopting  for  one  side 
the  mode  represented  in  No.  1,  and  on 
the  other  side  that  of  No.  2:  No.  3 
will  also  he  found  to  elucidate  the  right- 
angled  pressure  principle,  while  at  the 
same  time  it  shows  the  favorite  paral- 
lels to  the  line  of  flotation  ;  the  man- 
ner of  putting  together  is  less  compli- 
cated than  it  would  at  first  appear. — 
No.  1  must  be  put  together  in  layers, 
as  there  are  no  parallels,  but  the  lay- 
ers for  Nos.  2  and  3  may  be  dressed 
out  in  tin;  usual  manner,  and  glued  to- 
gether with  the  different  colors,  alter- 
nately, until  we  have  a  sufficient  bulk 
to  complete  the  model,  or  at  least 
double  the  half-breadth  ;  then,  by  com- 
mencing below,  as  No.  2,  for  example, 
taking  the  bevel  of  the  diagonal  from  the 
middle  line,  and  dressing  a  piece  to  the 
same,  as  shown  in  the  figure,  which  will 
contain  two  colors,  the  same  bevel  re- 
versed will  answer  for  the  second  piece, 
that  bevelling  as  much  standing  as  the 
first  does  under  ;  hence  it  will  at  once 
be  perceived,  that  it  is  only  necess;n\ 
to  slip  the  second  layer  up  or  down, 
until  the  opposite  colors  meet,  and  still 
the  line  is  continued,  if  the  materials 
are  of  equal  or  exact  thickness  ;  and 
without  this  is  attended  to  we  shall  fail 
to  accomplish  our  purpose,  for  at  every 
line  where  the  discrepancy  in  thickness 


is  found  there  will  be  a  break.  The 
middle  line,  it  will  readily  be  perceived, 
must  be  kept  true,  and  a  perfectly  fair 
plane,  and  square  from  the  water-lines 
from  which  to  bevel:  thus,  by  dressing 
our  pieces  to  the  bevel,  and  alternately 
sliding  the  layers  up  and  down,  we  ob- 
tain the  change  in  color,  which  exhibits 
lines  running  in  different  directions, 
and  which  are  contracted  and  expand- 
ed in  length  on  the  model,  when  in  its 
rotundity,  as  the  lines  are  more  or  less 
acute;  and  thus  the  inexperienced  be- 
come accustomed  to  measure  angles 
of  resistance  by  t  he  eye.  No.  3  is  quite  as 
easily  constructed  upon  the  same  princi- 
ciple,  and  will  show  the  diagonal  line, 
by  running  lines  in  the  direction  of 
the  points  of  the  diamonds;  and  No.  2 
will  also  exhibit  the  lines  that  illustrate 
the  direction  of  the  pressure,  by  run- 
ning other  lines,  also  intersecting  the 
points,  and  the  middle  of  the  diamonds. 
No.  1  will,  in  the  same  manner,  show 
the  form  of  the  water-lines.  Although 
we  have  assumed,  that  the  tables  may 
be  taken  from  models  made  in  this 
manner,  we  having  done  the  same,  yet 
it  is  attended  with  more  difficulty.  The 
author's  principal  design  in  introducing 
and  recommending  them  in  the  work, 
was  to  enable  mechanics,  who  depend 
upon  the  eye  alone  for  a  guide,  in  mo- 
delling vessels,  to  have  a  perspective 
chart  before  them,  and  thus  enabling 


MARINE    AND    NAVAL    ARCHITECTURE. 


115 


them  to  take  the  helm,  and  think  and 
act  for  themselves,  having  first  learned 
the  laws  of  resistance,  their  nature,  in- 
fluence and  extent,  or  in  other  words, 
the  equilibrium  of  fluids,  which  covers 
the  whole  ground-work  of  resistance. 
In  making  models  many  persons  sup- 
pose that  it  is  necessary  to  have  them 
made  upon  a  large  scale,  and  that  by 
so  doing  they  are  better  able  to  see  all 
the  discrepancies  more  readily  than  if 
the  scale  adopted  were  smaller ;  this  is 
a  great  mistake,  and  for  the  reason, 
that  the  larger  the  scale  the  less  one 
can  see  of  the  model  at  a  glance,  or 
without  turning  the  head  ;  if  we  desire 
to  grasp  the  whole  length  of  a  ship 
with  the  eye,  at  one  glance,  without 
turning  the  head,  we  find  it  necessary 
to  retire  at  a  distance  of  perhaps  ninety 
or  one  hundred  feet,  or  until  the  angle 
from  the  extremes  of  length,  to  the 
eye,  forms  sixty  degrees — as  this  is 
about  all  the  eye  can  grasp  with  effect 
at  once.  If  we  now  apply  this  angle 
from  the  eye,  to  the  model  made  upon 
a  three-eighths  scale  of  a  large  ship,  we 
will  find  that  we  are  too  far  off  to  dis- 
cover all  the  small  defects,  or  all  the 
unfair  spots  upon  its  surface,  and  if  we 
draw  nearer  to  the  model,  we  must  turn 
the  head,  and  can  only  see  part  of  the 
model  at  once;  and  when  this  is  the 
case  we  lose  part  of  the  effect  made  by 
the  bow,  for  example,  while  looking  at 


the  after-end,  and  are  prevented  from 
properly  balancing  the  ends  of  our 
model,  or  adapting  one  end  to  the 
other  ;  hence  it  will  appear  quite  mani- 
fest, that  if  the  model  were  made  upon 
a  smaller  scale,  we  could  see  the  whole 
at  once,  and  more  readily  discover  the 
inequalities  of  one  end  when  compared 
with  the  other ;  but  the  principal  ob- 
jection to  models  made  upon  a  small 
scale  remains  yet  to  be  examined,  viz., 
that  we  cannot  as  readily  discover  de- 
fects, they  being  smaller  than  they 
would  be  on  a  larger  model :  this  is 
true,  if  we  measure  both  models  by  the 
same  scale,  but  apply  the  appropriate 
scale  to  each  model,  and  we  shall  find 
the  full  place  of  an  inch  on  the  one,  is 
readily  discovered  to  be  an  equal  amount 
on  the  other.  It  requires  some  practice 
before  we  shall  become  sufficiently  ac- 
curate to  work  altogether  from  a  very 
small  scale  ;  but  after  having  been  able 
to  determine  what  we  want  from  the 
model,  by  the  small  scale,  we  shall, 
doubtless,  adhere  to  it,  and  we  will  find 
no  more  difficulty  in  working  from  an 
eighth,  or  the  tenth  of  an  inch,  than 
from  three-eighths,  or  the  half-inch 
scale.  We  must  not  forget,  however, 
that  the  model  must  be  perfectly  fair, 
not  only  on  all  the  lines,  but  in  every 
direction  ;  and  if  the  lines  do  not  fur- 
nish sufficient  proof  of  the  quality  of 
our  work,  in  this  particular,  we  should 


116 


MARINE    AND    NAVAL    ARCHITECTURE, 


applv  battens  in  other  directions,  trans- 
versely, diagonally,  vertically,  and  in 
every  other  direction  in  which  they 
may  be  applied ;  no  matter  what  the 
shape  may  be,  it  should  be  fair,  per- 
fectly so :  and  if  it  is  not  so,  it  is  little 
better  than  a  failure,  however  good  the 
shape  may  appear  to  be. 

It  is  to  be  regretted  that  so  many  me- 
chanics regard  the  model  of  a  ship  as  a 
mere  block  of  wood,  likethe  casual  obser- 
ver who  looks  upon  the  marble  in  the 
quarry,  without  being  able  to  discover 
the  statue  of  the  philosopher  or  the 
statesman.  With  such  a  glance  me- 
chanics will  never  be  able  to  rend  the 
veil  that  seems  to  hide  nature's  laws 
from  their  careless  vision.  But  the 
man  in  whose  mind's  eye  the  surplus 
of  the  material  itself  melts  away  before 
his  eager  gaze,  and  leaves  the  ship  in 
her  identity,  standing  out  in  drastic 
contrast  with  the  work  of  him  who 
works  only  with  his  hands,  we  say  it 
is  he  alone  who  will  be  able  to  approxi- 
mate that  degree  of  perfection  only  at- 
tainable through  the  medium  of  mathe- 
matical demonstrations.  Hundreds  of 
ships  are  modelled  with  but  little  regard 
to  shape,  like  shoes  made  upon  a  last, 
the  size  determining  their  utility  rather 
than  the  shape,  and  who  that  has  worn 
them  does  not  know,  that  unless  the 
sole  is  the  shape  of  the  foot  they  will 
be  uneasy,  and  wear  away  on  one  side 


faster  than  the  other  ;  so  with  the  ship, 
we  may  have  good  dimensions,  or  the 
ship  maybe  all  we  require,  as  to  size,  but 
the  bulk  of  the  size  may.  like  the  shoes, 
be  in  the  wrong  place,  and  she  will  be 
uneasy  in  her  motions, — a  dull  sailer, 
and  hard  on  her  spars  and  rigging,  sub- 
ject to  more  repairs  than  other  vessels. 
There  are  some  mechanics  that  will 
very  readily  assent  to  the  truth  of  the 
leading  feature  in  the  science  of  Ship- 
building, viz.,  the  equilibrium  of  fluids; 
but  talk  with  them  about  modelling- 
ships  and  they  will  deny  its  truth, — 
they  will  tell  us  how  much  harder  the 
water  presses  below  than  at  the  snr- 
face, — what  is  the  result  of  this  increa- 
sed pressure,  at  great  depths, upon  deep- 
sea  leads,  can-buoys,  bottles  hermetri- 
cally  sealed,  Sec,  and  adopt  various  me- 
thods to  explain  away  the  equilibrium 
of  fluids.  We  have  found  men  pre- 
senting claims  to  a  knowledge  of  the 
science  of  Ship-building,  and  ship- 
builders themselves,  in  the  ranks  of 
such  as  disclaim  experiments  of  a  tan- 
gible nature,  under  their  own  observa- 
tion,  the  results  of  which  cannot  mis- 
lead them,  to  follow  the  vague  and  in- 
definite theories  of  others.  That  water 
equilibriates  in  its  own  bulk  is  a  truth 
that  must  not  be  questioned  by  any 
man  who  expects  successfully  to  com- 
pete in  building  ships.  It  is  not  our 
province  to  follow   theorists,  and   give 


MARINE    AND    NAVAL    ARCHITECTURE. 


117 


reasons  which  they  themselves  have  not 
done,  for  this  extraordinary  pressure  at 
great  depths.  There  can,  however,  be 
little  doubt  that  the  water  in  itself  is 
of  greater  density  at  great  depths  than 
near  the  surface.  We  shall  not  pause 
to  inquire  how  far  below  the  surface  the 
boundary  line  maybe  found;  it  is  enough 
for  our  purpose  to  know,  that  far  below 
any  depth  immediately  connected  with 
navigating  the  ocean,  the  fluid  presses 
everyway  alike,  and  if  more  proof  is  re- 
quired in  addition  to  what  we  already 
have,  let  the  incredulous  man  make  a 
box  of  any  dimensions  he  may  find 
most  convenient,  or  best  calculated  to 
settle  the  question  ;  but  let  it  be  the 
same  size  at  the  top  as  at  the  bottom, 
make  it  tight,  and  set  it  afloat ;  mark 
its  water-line,  and  put  in  ballast  enough 
to  settle  it  one  foot,  the  weight  of  which 
must  bo  known  ;  continue  to  load  the 
box  until  within  the  last  foot,  and  he 
will  find  that  the  same  amount  of 
weight  is  required  to  displace  the  last 
foot  that  the  first  foot  required  ;  and 
this  is  the  case  within  the  range  of  all 
commercial  operations ;  if  we  make 
the  box  thirty  feet  deep  (which  will 
cover  the  draught  of  water  of  any  ship- 
of-the-line)  we  shall  find  that  the  re- 
sults are  the  same.  We  have  already 
given  an  exposition  of  this  subject,  but 
lest  any  of  our  readers  should  suppose 
that  we  advocated  more   breadth    and 


less  depth  in  ships,  on  account  of  the 
increased  pressure  on  a  heavy  draught 
of  water,  we  have  given  a  second  expo- 
sition. The  increased  pressure  arises 
not  from  the  draught  of  water,  but 
from  the  bulk  of  water  displaced,  (we 
now  allude  to  the  ship  at  rest,)  the  ad- 
dition of  depth  increases  the  weight  of 
the  ship  faster  than  a  proportionate  in- 
crease of  breadth  ;  hence  it  follows,  the 
ship  displaces  more  water,  by  making 
her  deeper,  than  by  adding  a  proportion- 
ate breadth  ;  and  it  will  be  at  once  per- 
ceived, that  the  deep,  narrow  ship,  is 
working  to  a  great  disadvantage,  carry- 
ing less,  and  of  herself  weighing  more, 
or  having  more  resistance  and  less  pro- 
pulsory  power,  or  unable  to  bear  an 
equal  amount,  which  is  the  same  in  ef- 
fect. We  have  shown,  that  steamers 
should  draw  less  water  than  sailing  ves- 
sels, not  on  account  of  the  supposed  in- 
creasing pressure,  with  an  increase  of 
depth,  but  because  of  the  increased  ne- 
cessity of  an  upright  position,  the  very 
reason  why  many  builders  advocate 
narrow  steamers,  the  same  reasons  ap- 
ply equally  to  sailing  ships'  breadth, 
adds  stability  in  both  cases.  Another 
error  demands  a  share  of  our  attention 
while  the  subject  of  making  models  is 
under  consideration.  It  is  almost  uni- 
versally believed  that  the  angle  of  resis- 
tance is  at  the  surface  of  the  fluid,  or 
at  the  lines  of  flotation  ;  how  far,  or  to 


118 


MARINE    AND    NAVAL    ARCHITECTURE 


what  extent,  this  is  the  case,  the  read- 
er may  be  able  to  judge  by  referring  to 
Plate  2,  the  angle  of  resistance  may 
there  be  seen  to  differ  widely  from  that 
of  the  line  of  flotation,  with  the  sheer 
and  half-breadth  plans ;  and  we  have 
set  apart  a  portion  of  a  subsequent 
chapter  for  an  exposition  of  this  sub- 
ject ;  Ave  shall  not  follow  it  farther  than 
to  point  out  the  line  thus  delineating 
the  angle  of  the  resistance  on  the  mo- 
del from  which  it  was  taken.  It  will 
be  seen  in  the  sheer-plan,  running 
from  the  stem  above  the  load-line, 
extending  aft  and  intersecting  the  sixth 
water-line  at  /.  from  thence  to  its  low- 
est plaee  at  the  centre  of  gravity, 
where  it  is  found  intersecting  the  se- 
cond water-line  ;  in  its  course  aft  it 
rises  toward  the  surface,  and  again  in- 
tersects the  sixth  water-line,  between 
frames  27  and  28,  and  ends  above  the 
plank-sheer  on  the  stern.  It  may  again 
be  traced  in  the  half-breadth  plan,  as 
seen  in  the  dotted  line  of  the  fore-body, 
or  section  1  of  Plate  2  ;  this  line,  it  will 
be  observed,  exhibits  the  angle  of  resis- 
tance on  that  model.  It  does  not  follow 
that  it  takes  the  same  direction  in  the 
sheer-plan  of  all  models,  or  of  any  two, 
(unless  they  are  alike  ;)  sufficient,  it 
doubtless  will  be,  for  the  present,  to 
say,  that  it  is  the  resultant  of  the  right- 
angled  pressure,  which  is  not  shown 
either  by  the   water-line,  the   diagonal 


line,  or  the  section  line.  There  is  an- 
other subject  connected  with  model 
making,  that  demands  a  share  of  our 
attention.  Ship-builders  usually  make 
their  models  with  a  straight  base-line, 
but  lay  the  keel  with  a  sag  of  several 
inches.  To  the  practice  of  laving  the 
keel  with  a  sweep  we  do  not  object ;  so 
far  from  objecting  we  advocate  a  prac- 
tice of  still  more,  but  we  would  have 
the  model  made  just  as  the  ship  is  re- 
quired. The  practice  of  making  a 
model,  and  altering  it  on  the  floor  of 
the  mould  loft,  exhibits  a  lack  some- 
where, either  that  the  builder  does  not 
know  what  he  wants,  or  that  his  mind 
cannot  grasp  the  ship  as  ;i  unit.  It  is 
quite  apparent,  even  to  the  casual  ob- 
server, that  no  man  can  discover  imper- 
fections in  form  on  the  floor,  as  well  as 
on  the  model ;  hence  the  importance 
of  making  the  model  just  as  we  want 
the  ship.  The  fore  part,  or  the  for- 
ward end  of  the  keel,  should  be  raised 
from  a  straight  base-line,  more  than  any 
other  part ;  the  reason  of  this  is,  that  it 
must  sustain  more  weight  than  any 
other  part  of  the  ship,  in  proportion  to 
the  buoyancy,  and  the  keel  is  soon  found 
to  be  lower  forward  than  elsewhere,  un- 
less kept  up  when  built.  But  this  is  not 
all ;  the  ship  is  worked  easier  by  having 
the  base-line  curved.  Some  persons 
have  supposed,  that  the  sweep  need  ex- 
tend  only   to  the   bottom    of  the  keel, 


MARINE    AND    NAVAL    ARCHITECTURE. 


119 


having  the  rabbet  straight,  or  nearly  so; 
this  can  be  of  but  little  advantage,  as  it 
leaves  the  flat  of  the  floor  very  nearly 
straight,  which  is  a  great  detriment  to 
the  speed  of  the  vessel,  while  it  is  no  ad- 
vantage in  any  respect.  If  the  model  is 
afac  simile  of  the  ship,  we  can  work  by 
the  sirmarks  for  our  sheer,  and  see  at  a 
glance  exactly  what  we  have.  There 
need  be  no  occasion  for  setting  the 
sheer  of  a  ship  in  the  usual  manner, 
with  a  rope;  if  she  is  like  the  model, 
and  the  necessary  amount  of  care  is 
taken  in  laying  down,  moulding,  fra- 
ming and  regulating,  the  sheer  may  at 
once  be  set  by  the  sirmarks.  These 
remarks  not  only  apply  to  the  sheer, 
but  to  all  parts  of  the  vessel.  We 
should  know  what  we  want  before  we 
begin  to  make  the  model,  and  having 
began  we  should  not  stop  short  of  satisfy- 
ing ourselves ;  and  we  may  rest  assured, 
that  if  we  cannot  accomplish  our  pur- 
pose on  the  model,  we  cannot  on  the 
floor,  or  on  the  ship,  however  much  we 
may  desire  so  to  do.     When  we  begin 


to  make  alterations  from  the  first  de- 
sign, we  cannot  tell  where  they  will 
stop  ;  one  change  leads  to  another,  and 
the  alterations  from  the  first  plan  keep 
pace  with  the  progress  of  the  vessel, 
and  when  finished,  sometimes  one  finds 
that  by  endeavoring  to  please  every- 
body, that  he  has  pleased  nobody,  not 
even  himself. 

Those  remarks  apply  to  the  internal 
arrangement,  as  well  as  to  the  shape 
of  the  ship,  and  if  we  progress  with 
our  work,  to  any  considerable  extent, 
before  making  all  the  arrangements,  we 
begin  before  we  are  ready,  and  time 
and  money  may  be  saved  by  attending 
to  this,  no  matter  how  short  the  time 
may  be  in  which  the  vessel  is  to  be 
built.  The  only  way  to  drive  work 
successfully  on  a  ship  is  to  begin  at  the 
model ;  one  day  spent  there  is  worth  a 
week  on  the  ship,  and  although  we  do 
not  always  carry  it  out,  yet  we  readily 
assent  to  the  truth  of  the  adage — that 
Time  is  Money. 


120 


MARINE   AND    NAVAL    ARCHITECTURE. 


CHAPTER     IV. 

Taking  off   Tables — Their  Distribution  on  the   Floor — Sheer  Plan — Sheering  in   General — Its  Intimate 

Connexion  with  the  appearance  of  Vessels. 


After  having  completed  our  model, 
the  first  consideration  is  to  determine 
the  distance  between  the  moulding 
edges  of  the  frames,  giving  the  great- 
est transverse  section,  or®  frame,  a  per- 
manent location,  or  the  starting  point 
for  future  operations.  Before  this  ques- 
tion  can  be  settled,  we  must  determine 
the  siding  size  of  the  timber  composing 
the  frames  of  the  ship,  and  the  thick- 
ness of  the  chock  that  separates  the 
faces  of  the  timbers,  having  reference 
to  the  finish  of  the  ship.  If  she  is  in- 
tended for  passengers,  with  lights  in  the 
side,  the  chock  should  be  smaller,  in 
order  that  the  light  may  come  between 
the  frames.  The  distribution  of  the 
timber  should  be  as  nearly  equalized  as 
possible,  both  for  strength  and  durabi- 
lity, and  having  arranged  the  timbering 
room,  we  may  mark  every  fourth  frame 
from  the  ®,  both  forward  and  aft,  un- 
til we  approach  the  ends,  when  every 
other  frame  alternately  should  be  also 
marked,  and  if  deemed  necessary,  every 
frame  may  be  marked  near  the  ends  of 
the  model  ;  circumstances  must  deter- 


mine its  necessity.  This  operation  will 
extend  the  whole  length  of  the  model, 
and  must  be  first  made  on  the  plane 
representing  the  middle-line  or  centre 
of  the  vessel.  After  having  made  these 
divisions  correctly,  measuring  by  the 
same  scale  upon  which  the  model  is 
made,  we  may  square  them  across  the 
water-lines,  from  the  base-line  to  rail  or 
upper  sheer,  these  being  the  fourth 
frames  midships,  and  are  usually  called 
the  spawl-frames.  It  is  now  necessary 
to  square  them  across  the  model  to  the 
outside  on  each  successive  sheer  and 
water-line  piece,  and  we  may  sepa- 
rate the  model  for  this  purpose  ;  after 
which  we  can  proceed  to  take  off  the 
dimensions  for  the  floor,  as  in  the  fol- 
lowing tables,  the  lower  water-line  being 
numbered  one,  and  those  above  in- 
creasing as  we  ascend  or  approach  the 
inscribed  line  of  flotation  at  the  sur- 
face of  the  water.  The  first  parts  of 
the  tables  required  are  those  pertain- 
ing to  the  sheer  plan,  and  exhibiting 
lengths  and  heights. 

We  may  now  see  to  the  mould-loft. 


TABLES  OF  PLATE  3. 


Names  of  Frames. 


Stem 


p ... 

D    .. 
B  ... 

1    .. 

5  .  . 

9  .. 
13  .. 
17  ... 
21  .  . 
25  ... 
29  ... 
}or33 
37   ... 


1st  Height 

It 


41  

45  

49   

53  

57  

61   

65  

69  

Cross  seam  on 

Rail  on  slern. . 
Rake  of  st'm  Cm  fr'm  1 
Rake  of  post  Pm  fr'm  * 
69  on  base  7  inches  * 


in.  8th 

6  3 

6  0 
1  4 
8  0 

3  0 

7  4 
10  5 

4  2 

10  0 
6  4 
2  6 

U  7 
1 

11  6 

0  0 
0 

1  2 

2  5 

5  4 
9  0 
1  0 
5  2 


2d  Height 

ft. 

15 

14 

14 

11 

13 

13 

12 

II 

11 

10 

Ml 

10 

10 

10 

III 

10 
10 
10 
10 
10 

11 
11 


in.  8th 

2  II 

7  ti 

5  0 

1  4 

8  4 

0  0 
4  4 

9  0 

3  5 
10  0 

6  3 

4  1 

2  0 

1  6 

2  0 

3  0 

4  1 

5  6 
8  0 
4  4 
2  6 

6  0 


ft.  111.8th: 


10  10 

11  10 


1 

5 

6 
2 
9 
6 
7 
2 
4 
4 
9 
11 
7 
1 
4 
7 
9 
4 
9  0 


3  W.  Line  4  W.  Line  5  W.  Line 
ft.  in.8ths    ft.  tn.Slhs    ft.  in.8ths 


5     0  6 


7  10  0 


10  1 
7  4 
40 
3  0  13 
7  4,14 
2  0  15 


0  7 

5  1 
8  0 
8  4 
4  5 

8  2 

9  0 

6  0 
0  0 

11  ti 

8  0 

9  6 
10  4 


9     0  0 


6  0 
9  0 
10  2  10 

4  1  13 
10  0,14 

3  6  15 
0  0  16 

5  0  16 

6  6|l6 

7  0 
6 
n 


6  W.  Line 


11  0 
3  3 

10  4 

3  Oil 

4  4 
1  6 

10 

11  0 
11  2 


9  10  0 


11 
II 
9 
3 
9 
0 
0  0 

7  0 
4  2 

8  0 

9  0 


4  0 

3  0 

10  0 

6  3 
3  0 

7  6 
6 

8  5 

10  0 

11  4 
0 
9 


ft.  in.  si  l,s 


10    7  4 


IstBre'dth  2.1  Iire'Jth 


ft.  in.Slhs    ft.  in.sths 


11     4  2  12    0  0 


7  4 


REMARKS. — Rise  of  Stem  on  Frame  1,  4  inches;  Water  Lines  2  feet  apart. 


10  4 
3  0 

5  6 

1  (I 

11  3 
8  6 

10  2  16 
10  6  16 

6  2  16 

7  -3  16 

8  0  16 
8  4  16 
8  2  16 
8  0  16 


7  4 
7  5 

6  0 
3  0 

7  0 

8  7 

9  6 
8  6 
7  7 
7  2 
6 
6 
4 


6  15 

2  15 
0  15 
0  15 


9  5 


11 
9 
8 
6 
3 

10 
li  6 
3  0 
0  0 
6  0 


0  0    9     7  4 


TABLES  OF  PLATE  5. 


a,a-J 

2 

.Of 

C 
3 

a 
3 

«5 

c 

►3 

c 

13 

O 

a 

B 

-C 

^ 

.G 

Names  of  Frames 

"Is 

0 

e   - 

a) 

2 

d 

is 

Bj 

is 

B 

Rake  uf  Stem  from  Frame 
U 

~JZ 

ft.  in.sths 

s 

£ 

2 

n 

s 

£ 

^ 

£ 

— 

" 

" 

ft. 

n.81  h* 

ft  in.8ths 

Stem    

5 

5 

10  3 

7  2 

9    3  5 
8  11  6 

11 
1(1 

1  2 
9  S 

0 

3  7 

n 

0 

I     5  2 

3 

7 

0  7 

9     5  3 

1st  Water  Line 
2d      do.      do. 

7  3 

11    5 

11   0 

2  3  6 

3  10  0 

a .... 

5 

1  6 

8    7  0 

10 

4  5 

0 

10  0 

1 

6  5 

2 

4  5 

3 

3  0 

4 

2  7 

5    2  6 

8 

0  3 

10 

4  6 

118  7 

o  .... 

4 

9  1 

8    2  4 

10 

0  4 

1 

11  0 

3 

6  0 

4 

10  0 

6 

0  5 

7 

2  6 

8    3  7 

10 

6   1 

11 

9  6 

12    3  7 

3d       do.      do. 

4    6  7 

M.... 

1 

4  0 

7  11  0 

9 

8  3 

3 

1  6 

5 

4  4 

7 

0  5 

8 

5  0 

9 

6  3 

10    5  2 

11 

9  3 

12 

3  6 

12    5  4 

4th     do,      do. 

5     1  6 

H  .... 

3 

8  6 

7    4  4 

9 

4  0 

li 

9  4 

8 

8  5 

10 

3  4 

11 

3  4 

ll 

11  3 

12    4  2 

12 

7  3 

12 

(i  7 

13     6  5 

5th     do.      do. 

5     7  6 

D  .... 

3 

3  6 

6  11  0 

8 

9  0 

s 

1  0 

HI 

8  7 

11 

11  4 

12 

6  4 

12 

9  4 

12  10  4 

12 

10  3 

12 

8  0 

12    7  0 

6th     do.      do. 

6     1  2 

®    ■•■ 

3 

0  0 

6    8  4 

8 

5  3 

8 

11  0 

11 

5  3 

12 

5  5 

12 

10  4 

13 

0  0 

13    0  0 

12 

11  0 

12 

9  0 

12    7  1 

1st  Breadth 

7    6  4 

4   .... 

.) 

10  5 

6    6  6 

8 

4  1 

8 

3  0 

11 

1  6 

12 

2  6 

12 

8  4 

12 

10  1 

12  10  0 

12 

8  6 

12 

6  5 

12     5  4 

21      do. 

8  11  4 

8   ..  .. 

■.' 

11  0 

6     7  3 

8 

4  4 

7 

2  4 

10 

2  0 

I  1 

7  0 

12 

3  4 

12 

7  4 

12    8  3 

12 

7  4 

12 

5  1 

12    4  0 

3d       do. 

10    5  0 

12  .... 

3 

1  3 

6    8  5 

8 

5  6 

5 

6  4 

8 

7  5 

10 

5  3 

11 

6  7 

12 

3  2 

12    6  0 

12 

5  5 

12 

3  5 

12    2  4 

Rake   of   Post 

16  .... 

3 

3  3 

6  11  0 

8 

7  3 

3 

6  6 

6 

5  4 

8 

8  0 

10 

3  6 

11 

5  5 

12     0  6 

12 

3  0 

12 

0  4 

11   11  3 

from  Frame 

26     0  0 

20  .... 

3 

74 

7    3  0 

8 

11  0 

1 

10  7 

3 

9  7 

5 

10  2 

7 

10  5 

9 

10  0 

11     12 

11 

11    1 

11 

9  6 

117  5 

At   Base  Line 

2    5  0 

22   .... 

3 

9  5 

7    5  0 

9 

1  4 

1 

4  3 

2 

8  5 

4 

3  0 

6 

1  2 

8 

2  5 

10    2  2 

11 

9  3 

11 

8  5 

115  5 

6th Water  Line 

3     1  0 

24   .... 

-1 

0  0    7    6  7 

9 

3  4 

0 

10  3 

1 

8  1 

2 

7  4 

3 

11  0 

5 

9  0 

8     1  7 

ll 

5  7 

11 

6  6 

11     3  2 

1st  Breadth    .. 

4    3  4 

26   .... 

4 

16   7    9  0 

9 

5  2 

0 

6  0 

0 

9  3 

1 

1  7 

1 

7  7 

2 

4  5 

3    8  4 

10 

9  2 

11 

4  6 

11      1  0 

3d      do 

7  11  4 

27  .... 

4 

3  0    7  10  0 

6 

6  2 

0 

3  5 

0 

4  2 

0 

5  2 

0 

6  6 

0 

8  5 

1     0  5 

9 

5  4 

11 

3  1 

10  11  2 

3d      do 

9     0  3 

Stern 

4 

4  0    H     13 

9 

9  4 

.... 

1 1 

0  6 

10    8  2 

REMARKS. — 1st  Water  Line  18  inches  above  base,  those  above  2  feet  apart.  Frames  2  feet  6  inches  apart.  Stern  Po=t  straight  12  ft. 
6  in.  above  Base  Line.  Knuckle  of  counter  on  centre  of  stern,  17  ft.  6  in.  above  Base  Line,  and  6  feet  4  inches  and  0-Hih  aft  of  frame  26. 
Round  ol  stern  at  counter  15  inches,  }  width  at  knuckle  10  feet  3  inches  square  from  middle  line  both  ways,  vertical  and  longitudinal. 
Round  of  stern,  at  2d  Breadth,  15  inches,  and  at  Rail  16  inches. 


_  r-*t~ 


o 


VJA 


0 


MARINE    AND    NAVAL    ARCHITECTURE. 


121 


If  we  have  not  floor-surface  sufficient  to 
lay  the  ship  down  her  whole  length, 
which  is  rarely  the  case,  (however  desi- 
rable to  those  who  are  unaccustomed 
to  the  operations  of  the  loft,)  but  have 
length  enough  to  accomplish  our  pur- 
pose by  dividing  her  into  two  sections, 
we  should  be  satisfied,  as  it  is  quite 
enough  length.  First,  strike  a  base-line 
on  one  side  of  the  floor,  the  length  of 
the  loft,  and  above  this  line  the  water- 
lines  may  be  set  off.  Having-  proceed- 
ed thus  far,  we  will  next  inquire  how 
much  length  is  required  from  the  0 
frame  to  the  front  of  the  cutwater,  as 
the  mould-loft  is  the  place  to  lay  down 
the  head,  as  well  as  the  ship  itself.  We 
should  have  length  enough  to  extend 
four  frames  at  least  into  the  after-body, 
but  eight  would  be  preferable.  When 
sufficient  lap  cannot  be  obtained,  we 
may  allow  no  room  for  the  head,  but 
let  the  stem  take  a  position  at  the  end 
of  the  loft  ;  the  fourth  frames  may  be 
set  off  on  base-line  and  squared  up.  If 
the  ®  frame  is  about  the  centre  of  the 
ship,  and  we  have  a  sufficiency  of 
length  for  the  head,  and  from  thence 
to  the  0  frame,  we  will  have  the 
length,  or  the  distance  the  head  pro- 
jects for  lap,  which  may  extend  to  five 
or  six  frames,  and  will  in  such  cases  be 
found  sufficient. 

We  will  assume,  in  the  case  before 
us,  that  the  loft  is  long  enough  for  such 


arrangement,  and  proceed  with  the 
work.  We  now  have  the  several  wa- 
ter-lines and  the  fourth  frames  in  the 
fore  and  after-body,  as  marked  on  the 
model. 

The  frames  may  now  be  marked,  as 
in  Plate  3,  or  as  is  the  usual  custom, 
which  is  to  number  the  after-body,  and 
naming  those  of  the  fore-body  in  al- 
phabetical order.  When  this  course  is 
adopted,  we  should  have  the  arrange- 
ment as  follows  :  ®  D,  H,  M,  Q,  &c. 
It  is  sometimes  thought  best  to  leave 
J  out  of  the  alphabet,  when  K  follows. 
This  arrangement  avoids  the  liability 
to  transpose  I  for  J,  when  framing. 

It  will  be  remembered  that  the  line 
we  have  denominated  the  base-line,  is 
also  the  middle-line,  or  the  centre  of 
the  vessel,  and  that  it  is  the  base-line 
for  both  bodies  of  the  ship,  the  fore  and 
the  after-body  ;  but  it  is  quite  evident, 
that  to  have  the  alphabet  marked  as  the 
example  just  shown,  in  the  usual  place, 
which  is  below  the  base,  would  shut  out 
the  numbers  of  the  after-body,  or  if 
they  were  also  marked  there,  it  must 
be  quite  apparent  that  there  would  be 
liability  to  mistakes.  In  order  to  avoid 
this,  we  may  number  or  letter  the 
fore-body,  above  the  sheer  lines.  For 
example,  suppose  that  we  have  every 
fourth  frame  lined  on  the  floor,  and 
that  our  loft  is  but  long  enough  for  a 
lap  of  four  frames,  we   begin  the  after- 


16 


122 


MARINE    AND    NAVAL    ARCHITECTURE. 


body  at  D  or  29,  from  which  to  ®  will  be 
t  he  lap.  We  then  have  0 4,8, 12, 16,20, 
24,  &c,  up  to  36;  or,  as  in  Plate  3,  ® 
37,  41,  45,  49,  53,  57,  61,  65,  69.  In 
the  fore-body  we  have  ®  where  40,  or 
where  73,  (in  Plate  3,  Section  2,)  would 
be  in  the  after-body,  which  makes  pro- 
vision lor  the  lap  of  4  frames;  as  D,  or 
29,  are  found  in  both  bodies:  the  stern 
would  project  nearly,  or  quite  the  dis- 
tance beyond  36  that  the  fourth  frames 
are  apart.  It  then  follows,  if  40  and 
®  would  be  the  same  frame,  assuming 
Plate  3  to  have  been  lettered  forward, 
instead  of  numbered,  36  and  D  would 
also  be  the  same  frame  ;  32  and  H 
would  also  be  the  same  frame.  This 
arrangement  is  precisely  the  same  as 
in  Plate  3,  with  this  exception,  that 
in  the  latter  the  numbers  begin  for- 
ward, at  the  foremost  square-frame,  and 
continue  aft ;  the  few  frames  forward 
may  be  marked  in  alphabetical  order. 
This  arrangement,  or  that  shown  in 
Plate  2,  or  the  present  course,  as  al- 
ready described,  may  be  adopted,  with 
equal  success ;  it  makes  no  difference 
which,  provided  we  continue  in  force 
throughout  the  method  we  first  adopt. 
When  the  vessel  is  long,  and  there  are 
more  frames  in  the  fore-body  than  let- 
ters in  the  alphabet,  we  recommend  the 
method  adopted  on  the  ocean  steamer,  of 
taking  up  the  small  Italic  alphabet,  as 
in  Section  1  of  Plate  2,  or  as  shown  in 


the  tables  of  Plate  5,  after  having  ex 
hausted  the  Roman  alphabet.  We  have 
assumed,  in  the  arrangement  now  com- 
menced on  the  floor,  that  the  two  bo- 
dies on  load-line  are  of  equal  length, 
or  nearly  so,  as  in  Plate  3 — heme,  it 
will  be  quite  apparent,  that  if  we  have 
room  to  append  the  head,  that  the  fore- 
body  requires  more  length  of  loft  than 
the  after-body,  and  to  balance  the  bo- 
dies, we  have  given  all  the  lap  to  the 
after-body. 

We  have  been  thus  particular  in 
describing  arrangements,  lest  the  read- 
er, who  may  not  be  familiar  with  the 
operations  of  the  loft,  should  get  con- 
fused, and  lose  the  force  of  our  expo- 
sitions. There  is  no  difficulty  in  laying 
down  the  vessel  entire,  even  though  it 
may  require  three  lengths,  as  in  Plate 
2,  before  making  moulds,  and  at  the 
same  time  have  free  and  ready  access 
to  every  part  of  the  operation,  provided 
the  arrangements  are  clear  and  com- 
prehensive in  our  minds.  When  our 
floor  is  too  short  to  lay  the  vessel  down 
in  two  lengths,  we  have  only  to  so  ar- 
range the  three  sections,  that  each 
fourth  frame  will  represent  three  frames, 
one  of  each  section,  and  numbering  the 
after-section  at  the  base-line,  the  mid- 
dle section  at  load-line,  and  the  for- 
ward section  above  the  rail,  or  at  the 
side  of  the  loft,  [t  has  been  quite  com- 
mon, where  floor-room  has  been  insuffi- 


MARINE    AND    NAVAL    ARCHITECTURE. 


123 


cient  for  the  operation  in  one  or  two 
lengths,  to  lay  down  one  section  of  the 
vessel,  and  make  the  moulds,  before 
laying  off  the  second.  This  may  be 
necessary  where  we  are  in  great  haste, 
but  it  is  seldom  attended  with  any  real 
advantage.  True,  we  get  some  moulds 
a  few  days  sooner,  but  our  supply  is 
suddenly  cut  off,  and  we  are  waiting  for 
a  second  ;  whereas,  had  we  continued 
the  operation  of  laying-off,  at  the  time 
the  moulds  came  from  the  second  sec- 
tion, we  should  have  received  them  from 
the  first,  and  they  would  have  been 
continuous.  But  this  is  not  all ;  ves- 
sels are  found  to  be  more  difficult  to 
regulate,  and  are  not  as  fair  when  thus 
laid  down,  for  the  following  reasons  : 
First,  should  there  be  any  discrepancy 
in  one  of  the  lines,  we  do  not  know 
which  frame  to  charge  with  the  fault, 
unless  we  have  another  section  at  hand. 
Supposing  that  after  the  first  section  is 
laid  down,  and  the  moulds  made,  we 
discover  in  sweeping  in  the  frames  of 
the  second  section,  that  one  or  more 
lines  must  be  altered  to  make  the  frame 
fair ;  but  we  cannot  alter  without  ex- 
tending the  same  beyond  the  lap  into 
the  first  section  ;  hence  we  see,  that 
it  is  in  this  manner  we  often  take  what 
we  do  not  want,  or  woidd  not  have,  if 
we  could  go  over  the  work  again  ;  but 
this  cannot  be  done,  as  the  timber  is 
perhaps  all  worked,  and   thus  men  are 


driven  in  their  haste  to  give  their  as- 
sent  to  what  they  know  to  be  wrong. 
These  discrepancies,  to  a  man  of  taste, 
are  like  a  night-mare,  brooding  over 
his  mind,  and  mirroring  and  expanding 
them  before  him. 

Where  the  model  is  made  by  the  eye, 
and  dependent  upon  the  same  on  the 
floor  of  the  loft,  the  vessel  should  be  all 
laid  down,  or  at  least  the  lines  should 
be  proven  in  their  whole  length,  before 
any  moulds  are  made.  That  vessels 
can  be  laid  down  on  a  floor  the  size 
of  the  body  plan,  does  not  admit  of  a 
doubt,  but  it  requires  more  time,  and 
is  more  liable  to  error ;  but  when  we 
leave  the  eye,  and  make  an  exchange 
for  a  system  of  proportions  that  can  be 
carried  out  by  calculations,  we  are  less 
dependent  upon  the  second  section  for 
proof  of  the  first,  or  upon  the  third  for 
proof  of  the  second. 

If  our  floor  should  not  be  sufficiently 
wide  to  lay  down  the  vessel  in  her 
whole  depth,  we  may  divide  the  depth 
into  two  sections ;  the  boundary  lines 
of  the  lower  section  should  in  such  case 
be  the  base  and  load-line,  and  of  the 
upper  section  the  base  may  be  regard- 
ed as  the  load-line,  and  the  sheer-lines 
above.  Having  our  arrangements 
made  to  the  best  advantage  for  eluci- 
dating the  operations  on  the  floor,  we 
shall  now  proceed  to  take  oft*  the 
heights,  as  obtained  from  the  model,  on 


124 


MARINE    AND    NAVAL    ARCHITECTURE. 


every  fourth  frame  above  the  load-line, 
and  to  set  oil*  the  stem  and  stern-post 
as  measured  on  the  water  and  sheer- 
lines,  from  a  particular  frame  designated 
for  tin;  purpose, as  in  the  tables  of  Plates 
3  and  4.  Those  lines  at  opposite  ends 
of  the  loft,  form  the  longitudinal  boun- 
dary-line of  the  ship — the  line  repre- 
senting the  stem  is  the  inside,  or  aft  side 
of  the  same,  and  whether  we  adopt  the 
proposed  improvement  or  not,  of  hav- 
ing the  stem  inside  the  ship,  it  does  not 
alter  the  lines  on  the  floor.  This  line 
extends  from  the  rail  to  its  intersection 
with  the  base-line,  which  should  have 
some  rise  at  or  near  its  intersection 
with  the  stein;  hence  it  is  quite  clear, 
that  the  margin-line,  or  line  showing  the 
inside  of  the  stem,  is  but  a  continuation 
of  the  base-line,  although  bearing  ano- 
ther name,  beyond  a  certain  point. 

This  also  applies  to  the  stern-post,  as 
high  as  the  cross-seam,  so  that  in  truth 
the  base-line  extends  from  the  rail  to 
the  cross-seam. 

We  are  thus  particular  in  defining 
this  boundary-line,  on  account  of  the 
ending  of  lines,  a  part  of  the  operation 
that  is  usually  so  perplexing  to  begin- 
ners. From  the  cross-seam  we  may 
now  extend  the  counter  archboard  and 
stern,  remembering  that  the  part  of  the 
stern  shown  in  this  line  is  at  the  cen- 
tre, and  consequently  the  longest  pari, 
or  that  farthest  aft. 


We  now  have  the  sheer-plan  of  both 
bodies,  that  of  the  after-body  extend- 
ing from  the  stern  at  the  centre,  to 
frame  29,  or  frame  1),  showing  t  lit* 
heights  of  all  the  frames  between  those 
points,  at  the  several  sheers,  and  all  the 
water-lines  running  parallel  to  the  base, 
at  their  respective  heights,  and  termi- 
nating successively  above  each  other, 
on  the  inside  of  the  stern-post. 

The  same  remark,  made  of  the  stem, 
as  to  its  being  inside  or  outside  of  the 
ship,  as  they  now  are,  applies  to  the 
stern-post  also.  As  the  sheer  plan 
shows  lengths  and  heights  only,  the  af- 
ter-body, by  previous  arrangement,  is 
numbered  below  the  base-line.  The 
fore-body  is  likewise  represented  in  the 
same  base-line,  water-lines,  and  frames, 
the  water-lines  being  parallel  to  the  base, 
and  the  distance  between  the  frames 
being  equally  spaced.  We  have  the 
same  frames  in  the  fore-body  that  are 
shown  in  the  after-body,  and  may  be 
numbered  or  lettered,  as  before  stated, 
on  the  floor  above  the  sheer-lines. 

Having  given  the  boundary-line  of 
the  sheer  plan,  a  word  of  instruction 
may  not  be  out  of  place  in  relation  to 
sweeping  in  the  sheer  of  the  two  bodies. 
We  should  remember,  that  the  round 
edge  of  the  batten  is  the  best  to  look  at  in 
fairing  the  sheer,  or  other  lines  on  the 
floor,  and  they  should  lay  on  their  flat, 
the  edge  to  the  spots.      We  may  place 


MARINE    AND    NAVAL    ARCHITECTURE, 


125 


the  battens  to  one  or  all  the  sheers,  at 
the  same  time  ;  if,  however,  the  sheers 
taper,  one  at  a  time  is  quite  sufficient ; 
when  they  are  parallel,  they  may  all  be 
regulated  at  the  same  time  to  advantage. 
The  sheer  of  the  after-body  should  be 
swept  first  in  this  instance,  because  the 
lap  is  appended  to  this  plan,  and  after 
regulating  the  sheers  of  this  body,  and 
marking  them  on  the  floor,  we  may 
take  the  heights  at  0  and  29,  as  in 
Plate  3,  Section  2,  or  on  ®  and  D,  ac- 
cording as  the  arrangement  is  made  in 
numbering  or  lettering  the  fore-body. 
Those  heights  are  to  remain  unaltered 
when  regulating  the  sheer  of  the  fore- 
body,  and  although  the  sheer  of  the 
two  bodies  will  be  found  to  cross  each 
other,  and  are  thus  kept  apart,  there 
will  be  no  cause  for  difficulty  in  tra- 
cing them.  We  may  next  set  off  the 
thickness  of  the  plank  below  the  base- 
line, at  the  termination  of  the  straight 
rabbet  on  the  keel  forward  ;  square 
from  the  same,  and  continue  to  do  so, 
at  intervals,  on  the  stein,  its  entire 
length  to  the  head,  measured  square 
from  the  line  representing  the  inside  of 
the  stem.  This  operation  will  be  re- 
quired on  the  stern-post  likewise,  and 
measured  square  from  the  inside  of  the 
post. 

It  will  be  discovered  that  wer£  the 
rabbet-line  extended  along  the  keel,  that 
we  should  have   two   continuous  lines 


from  the  cross-seam,  or  the  margin- 
line,  as  it  is  called  by  many,  to  the  head 
of  the  stem,  or  to  the  lower  side  of  the 
plank  sheer,  known  as  first  height  in 
Plate  3,  and  the  space  between  these 
lines  is  to  be  filled  with  the  end  of  the 
plank,  on  the  stem  and  post,  and  with 
the  edges  of  plank  on  the  keel. 

The  forward-line  on  the  stem,  the 
lower-line  on  the  keel,  and  the  after- 
line  on  the  post,  represent  the  wood 
ends  on  the  post  and  stem,  and  the 
garboard  seam  on  the  keel ;  but  the 
direction  from  this  seam  inward,  or  aft 
from  the  stem,  forward  from  the  post, 
and  upward  from  the  keel,  remains  yet 
to  be  defined.  It  is  important  that  this 
part  of  the  work  should  be  clearly  de- 
scribed and  understood,  inasmuch  as  it 
has  been  considered  a  complex  problem, 
in  practical  operations,  mostly  on  ac- 
count of  the  constant  change  that 
takes  place  in  the  bevel  of  the  rabbet. 
We  may  draw  the  sweeps  for  the  ends 
of  the  water  and  sheer-lines,  before  or 
after  setting  off  the  half  breadths  on 
their  respective  frames.  We  will,  in 
the  case  before  us,  proceed  to  end  the 
lines  in  the  half-breadth  plan,  com- 
mencing with  those  on  the  stem.  In 
order  to  render  the  ending  of  water- 
lines  clear  and  comprehensive,  we  shall 
divest  the  matter  entirely  of  every  ves- 
tige of  the  hereditary  notions  that  have 
hung  around  this  subject   for  so  many 


126 


M  A  I!  1  N  E   AND    .NAVAL    ARCHITECTURE. 


years.     We  have  shown  that  the  line 

showing  the  end  of  the  model  on  the 
how  and  post,  in  its  continuation,  also 
represented  the  base-line,  or  top  of  the 
keel. 

It  will  be  necessary  to  set  off  above 
the  base-line,  in  the  sheer  plan,  which 
is  also  the  middle-line  in  the  half- 
breadth  plan,  half  the  size  of  the  stem 
and  stern-post  ;  those  lines  need  ex- 
tend no  further  than  the  rake  of  the 
stem  and  stern-post  requires,  and  will 
represent  the  siding  size  of  those  im- 
portant parts  of  the  ship.  Should  the 
stem  be  larger  at  the  head  than  the 
size  of  the  keel,  which  is  highly  ne- 
cessary,  half  of  that  difference  will  be 
shown  in  the  opening  between  this  line, 
which  is  called  the  side-line,  and  the 
middle-line.  The  same  remark  is 
equally  applicable  to  the  stern-post,  and 
its  size,  when  determined,  can  be  shown 
in  the  same  manner  by  the  space  be- 
tween the  middle-line  and  this  side-line. 
This  method  is  applicable  to  the  pre- 
sent mode  of  adjusting  the  stem  and 
post  outside  of  the  ship,  with  the  ex- 
ception  of  the  thickness  of  the  plank, 
which  always  extends  beyond  this  boun- 
dary-line, forward  on  the  stein,  down- 
ward on  the  keel,  and  aft  on  the  stern- 
post.  This  simple  problem  has  been 
rendered  abstruse,  in  consequence  of 
writers  having  confounded  the  final 
termination  of  lines  with  their  intersec- 


tion with  the  side-line,  or  the  termina- 
tion for  the  inside  of  the  plank  with 
that  of  the  outside. 

This  is  wholly  unnecessary  ;  all  the 
knowledge  the  pupil  requires  in  the  loft 
upon  this  subject,  is  enough  to  enable 
him  to  mark  the  spot  where  the  water 
or  sheer-lines,  in  their  rotundity,  cross 
the  side-line  on  the  inside  of  the  plank. 
It  is  plain  that  the  outside  corner  of  the 
stein  on  the  model,  is  the  inside  of  the 
plank,  and  this  represents  the  inner  cor- 
ner of  the  rabbet.  It  is  also  plain  that  we 
cannot  have  the  wood  ends  on  the  out- 
side of  the  plank  of  the  same  sweep  or 
shape  as  the  inside  of  the  stem,  if  we 
adhere  to  this  inside  or  corner  line  for 
the  ending  of  all  the  lines,  unless  we 
cut  an  unfair  rabbet,  and  subject  the 
butts  in  some  parts  to  a  strain  in  caulk- 
ing that  would  be  likely  to  start  them. 
But  this  is  not  all : — the  shape  would 
be  of  less  consequence  than  the  dan- 
ger to  be  apprehended  from  the  oakum 
following  the  seam  that  divides  the  stem 
from  the  apron,  and  instead  of  caulk- 
ing the  butts  of  the  plank,  the  stem  and 
the  apron  would  be  subjected  to  an  un- 
necessary strain,  while  the  butt  would 
remain  uncaulked. 

To  obviate  this,  and  still  bring  the 
lines  to  their  proper  place,  it  is  only 
necessary  to  square  this  corner  or  mar- 
gin-line, out  to  the  side-line,  which 
is  done  by   squaring  down   the    water 


MARINE    AND    NAVAL    ARCHITECTURE 


127 


and  sheer-lines  from  their  intersection 
with  the  line  showing  the  inside  of  the 
stem  and  stern-post  to  the  side-line  ; 
those  spots  being  marked,  we  may 
take  a  pair  of  compasses  and  set  them 
to  the  thickness  of  the  plank  at  the 
rabbet,  (which  should  be  less  than  on 
the  other  parts  of  the  ship,  as  we  shall 
show.)  We  may  now  apply  one  leg"  of 
the  compasses  to  this  spot,  and  the 
other  in  the  side-line  forward,  turning 
on  the  last  leg  and  sweeping  inward, 
thus  marking  on  the  floor  a  quarter 
circle  in  the  direction  of  the  line,  as 
shown  in  Plate  4.  Some  persons  may 
suppose,  that  because  the  rabbet  is 
swept  on  the  stem,  that  this  outside 
line  should  be  squared  down  ;  but  this 
error  will  appear  quite  manifest,  if  the 
individual  who  is  thus  revolving  the 
subject  in  his  mind,  will  take  a  model 
in  his  hand  and  examine  the  subject, 
after  reading  our  remarks  upon  this 
particular  part  of  the  operation. 

In  those  expositions  we  have  as- 
sumed the  dead  wood  to  be  of  the 
same  thickness  as  that  of  the  stem,  and 
the  bearding-line  will  vary  proportion- 
ately as  the  dead  wood  is  thicker  or 
thinner  than  the  keel.  The  impor- 
tance will  at  once  appear  of  making 
the  stem,  stern-post  and  dead  woods, 
the  same  as  laid  oft'  on  the  floor 
in  thickness.  There  is  an  apparent 
discrepancy  in   thus  ending   lines,  con- 


sequent upon  the  rake  of  the  stem. 
It  is  evident  that  the  water-lines  in  the 
sheer-plan,  if  extended  to  the  forward 
edge  of  the  rabbet,  would  show  an  in- 
creasing length  on  each  line,  as  we  de- 
scend toward  the  keel,  while  the  rab- 
bet remained  the  same  size,  the  whole 
length  of  the  stem,  when  measured 
square  from  the  margin,  and  in  conse- 
quence of  the  increasing  rake  of  the 
stem  as  we  descend,  a  rabbet  that  is 
only  three  inches  on  the  square,  may 
be  found  to  measure  a  foot  on  the  wa- 
ter-line. 

Now,  it  will  appear  quite  manifest, 
that  if  the  outer  edge  of  the  rabbet 
were  squared  down  to  the  side-line,  and 
the  thickness  of  the  plank  swept  in 
square,  either  from  this  point  or  from 
the  size  of  the  rabbet  aft  of  this  point, 
the  ending  would  not  compare  with  the 
half-breadths,  as  taken  off  the  frames, 
and  as  a  consequence,  would  be  unlike 
the  model.  Thus  we  discover  that  the 
margin  of  the  stem  is  the  fixed  point 
for  the  intersection  of  the  sweep  with 
the  side-liue,  the  centre  of  which  sweep 
is  as  far  forward  as  the  size  of  the  rab- 
bet, when  measured  square  on  the 
stem  ;  the  circle  once  obtained, we  have 
the  ending  of  the  line,  as  it  matters  not 
how  sharp  or  how  full  the  vessel  may 
be,  the  line  intersects  the  circumference 
of  this  circle,  and  thus  provision  is 
made  for   the  plank,  which  will   be  in- 


128 


MARINE    AND    NAVAL    ARCHITECTURE, 


variable,  while  our  compasses,  or  the 
sweep  they  make,  remains  unaltered. 
The  bearding-line  is  a  second  rabbet- 
line  formed  by  the  lines  showing  the 
inside  of  the  plank,  in  their  intersec- 
tion with  the  side-line. 

It  will  be  remembered,  that  in  our 
expositions  of  the  manner  of  ending 
lines,  the  line  swept  in,  forward  of  the 
margin-line,  for  the  inside  of  the  stem, 
is  the  boundary-line  for  the  outside  of 
the  plank,  consequently  the  groove,  or 
rabbet,  commences  here  and  cuts  in- 
ward,  square  from  the  line  in  its  rotun- 
dity, until  it  reaches  the  required  depth 
of  the  rabbet,  when  it  takes  the  course 
of  the  line  and  emerges  at  the  side-line 
on  tlie  inside  of  the  plank,  as  shown  in 
Plate  4.  This  line  is  necessary  to  de- 
termine the  moulding  size  of  the  dead 
wood,  both  forward  and  aft,  in  the 
sheer-plan,  as  the  cants  terminate  their 
moulding  and  bevelling  edges  at  this 
line — hence,  it  must  follow,  that  to 
render  the  heels  of  the  cants  secure, 
the  dead  wood  must  reach  a  sufficient 
size,  or  depth,  to  cover  their  heels 
that  come  against  the  dead  wood. 

Those  remarks  apply  equally  well  to 
both  ends  of  the  ship,  and  this  part  of 
the  operation  will  be  required  before 
the  ship  is  all  laid  oft"  on  the  floor,  al- 
though many  defer  this  part  of  the 
work  until  a  later  period,  and  the  con- 
sequence is,  that  the  ends  of  the  ship 


do  not  keep  pace  with  the  middle,  or 
more  bulky  parts.  It  is  necessary  to 
forward  the  bow  and  stern  of  the  ves- 
sel as  fast  as  possible,  in  order  to  keep 
them  in  the  same  state  of  advancement 
with  other  parts  of  the  ship,  for  the 
following  reasons: — there  is  a  great 
amount  of  work  to  be  done  within  a 
small  compass,  and  as  a  consequence, 
but  few  hands  can  work  to  advantage ; 
hence,  the  necessity  of  obtaining  the 
required  shape,  dimensions,  and  moulds 
pertaining  to  those  parts,  as  early  as 
practicable. 

Many  builders  in  Europe,  and  some 
in  the  United  States,  make  a  dead  wood 
mould  for  both  ends  of  the  ship.  This 
is  altogether  unnecessary — the  stem 
mould  being  all  that  is  required — the 
size  of  which  is  of  no  farther  conse- 
quence than  to  be  of  sufficient  size  to 
embrace  the  rabbet,  bearding  and  base- 
lines. 

Naval  Architects  have  confused  the 
minds  of  their  readers,  by  making 
many  more  lines  than  is  absolutely  ne- 
cessary, in  laying  oft"  on  the  floor,  while 
maritime  enterprise  leads  to  the  short- 
est, or  most  direct  course,  to  arrive  at 
the  same  end.  European  works  upon 
this  subject,  even  those  of  latest  dates, 
confound  this  whole  subject  with  a  de- 
scription of  an  inner  and  an  outer  rab- 
bet, evidently  following  the  directions 
laid  down  in  the  musty  folios  of  the  past. 


MARINE    AND    NAVAL    ARCHITECTURE. 


129 


The  mechanic  who  would  undertake 
to  follow  those  directions,  with  no  other 
instructions  than  there  found,  will  find 
himself  perplexed  and  confused,  but 
not  instructed.  What  we  have  already 
said  in  substance,  we  now  repeat  in  so 
many  words :  we  need  recognize  but 
two  lines  on  the  floor  as  immediately 
connected  with  the  rabbet — the  first  is 
the  inside  of  the  stem  or  post,  and  base- 
line, which  we  have  for  distinction 
called  the  margin  ;  the  second  is  the 
bearding-line,  which  is  the  forward 
part  of  the  rabbet  on  the  dead  wood  aft, 
and  the  after  part  of  the  rabbet,  on  the 
dead  wood  forward  ;  the  outside  of  the 
plank  need  not  be  shown  on  the  floor. 

When  we  determine  to  put  the  stem 
and  the  stern-post  inside  of  the  ship, 
for  reasons  given  on  page  102,  and  il- 
lustrated in  Fig.  14,  we  need  not  end 
the  lines,  or  form  the  rabbet,  until  after 
we  have  distributed  the  tables  or  half- 
breadths,  on  their  respective  frames  in 
the  half-breadth  plan ;  we  may  set  off 
both  bodies  before  sweeping  either,  re- 
membering to  sweep  in  that  body 
first,  which  has  the  lap  appended  to 
it.  When  we  adopt  the  internal 
stern-post,  we  may  square  down  the 
margin-line  from  the  sheer  to  the  half-. 
breadth  plan,  at  the  several  water  and 
sheer-lines.  We  may  obtain  a  set- 
ting-off  on  those  spots,  thus  squared 
down,  by  taking  half  the  thickness  at 


those  terminations,  from  the  model,  or 
draught,  as  shown  in  Plate  3,  Sections 
1  and  2.  Having  distributed  the  half- 
breadths  of  the  water-lines,  we  may 
proceed  to  place  the  battens  to  the 
spots  on  the  several  frames.  It  is  de- 
sirable to  regulate  all  the  water-lines  at 
the  same  time,  or  to  have  all  the  bat- 
tens required  for  this  purpose  on  the 
floor  at  the  same  time,  as  one  line  de- 
termines, to  some  extent,  the  correct- 
ness of  the  other.  The  variations, 
however,  will  be  inconsiderable,  if  pro- 
per care  is  taken  in  preparing  the  ta- 
bles from  the  model ;  the  battens  will 
come  together  at  their  ending,  but  they 
may  lay  one  above  the  other  until  re- 
gulated. 

Some  builders,  while  regulating  the 
half-breadth  plan,  select  a  convenient 
part  of  the  floor,  and  lay  oft'  the  trans- 
verse sections  of  the  ship  at  the  same 
time.  Those  sections  exhibit  another 
view  of  the  vessel,  and  fall  within  each 
other,  showing  the  shape  of  every 
square  frame  at  its  moulding-edge,  or 
at  the  inside  of  the  plank;  it  is  usually 
called  the  body-plan,  like  that  of  Sec- 
tion 4  of  Plate  2,  or  that  of  Plate  5, 
from  the  tables  of  the  same.  The  half- 
breadth  one  way,  and  the  entire  depth 
of  the  ship  the  other,  is  necessary  to 
lay  down  the  fore  or  after-body.  This 
plan  is  bounded  by  a  middle-line,  which 
represents  the  centre  of  the  stern-post 


17 


130 


M  A  R  I  N  F.    A  X  D    N  A  V  A  L    A  R  CHITECTUI!  I.. 


for  the  after-body,  and  requires  a  base 
and  water-lines  the  same  as  the  sheer- 
plan,  and  it  is  important  that  the  wa- 
ter-lines should  be  spaced  the  same  as 
in  the  sheer-plan,  else  we  may  find  dis- 
crepancies which  we  would  hardly  be 
willing  to  accredit  here  ;  and  in  all  our 
measurements  on  the  floor,  we  shonld  j 
remember  that  there  is  no  room  for 
the  common  expression,  that  is  near 
efioiifrh. 

There  is  a  large  surplus  about  every 
ship-yard,  without  carrying  it  from  the 
mould-loft  with  the  moulds  and  bevel- 
lings ;  the  winding  of  the  timber,  sup- 
posed to  be  sided  fair,  the  large  quan- 
tity that  is  not  sided,  and  the  bad  be- 
velling of  the  frame,  in  addition  to  con- 
tingent circumstances,  growing  out  of 
ignorance  and  carelessness,  will  afford 
the  careful  man  abundant  reason,  when 
the  ship  is  raised,  to  say,  that  with  all 
his  care,  she  is  not  as  near  the  mark  as 
he  expected  she  would  be. 

When  this  method  is  adopted,  the 
same  tables  may  be  worked  from  for  this 
plan,  that  have  been  used  for  the  half- 
breadth  plan.  The  line  showing  half 
the  size  of  the  keel  and  post,  in  the 
naif-breadth,  must  be  set  oft'  from  the 
middle-line,  the  same  in  both  plans ;  at 
the  base-line  the  space  must  be  half  of 
the  size  of  the  keel,  and  at  the  cross- 
seam,  half  that  of  the  post  at  that 
height,  as  in  Plate  5. 


The  heights  of  the  sheer-line  must 
be  taken  from  the  floor,  measuring  from 
the  load-line  to  each  height  on  its  re- 
spective frame  in  the  after-body;  they 
should  be  taken  on  a  small  batten, 
and  transferred  to  both  sides  of  the 
after-body  plan.  This  being  done,  lines 
may  be  stricken  across  the  half-body 
plan,  representing  the  height  of  every 
fourth  frame,  and  numbered  to  cor- 
respond with  the  sheer-plan.  If  we 
have  battens  enough,  (and  we  never 
lose  by  having  a  good  supply,)  we  may 
run  in  the  sheer-lines  in  the  half- 
breadth,  and  then  we  •  prepared  to 
sweep  the  fourth-fram  in  the  body- 
plan.  The  battens  may  row  be  placed 
by  the  spots,  as  taken  fr  i  the  tables, 
making  the  variations  U  correspond 
with  those  of  the  half-breadth.  .  The 
heights  in  the  sheer-plan  are  colled 
breadths  in  the  half-bit  dth  and  body- 
plans. 

We  now  have  the  whole  after-body 
of  the  ship  spread  out  be  ore  us  in  three 
separate^plans,  and  it  ma  readily  be 
perceived  that  the  one  sh  Id  corres- 
pond with  the  other,  and  as  we  have 
the  spots  taken  from  the  same  tables 
in  both  bodies,  or  plans,  whatever  va- 
riation we  make  in  one  body  must  be 
made  in  the  other.  Thus  the  longitu- 
dinal planes  are  expanded  to  the  full 
size  of  the  ship,  as  seen  by  the  water- 
lines,  (as  they   are   commonly   called,) 


A 


MARINE  AND  NAVAL  ARCHITECTURE. 


131 


or  the  battens  showing  those  lines,  and 
the  shape  of  the  frames  are  also  shown, 
as  in  Plate  5.  It  must  be  remember- 
ed not  only  that  the  breadths  at  every 
water-line  and  sheer-line  must  agree 
in  both  plans,  but  that  the  lines  must 
be  fair,  as  well  as  the  frames ;  should 
there  be  a  wide  departure  from  a  spot 
made  or  measured  from  the  tables,  we 
should  go  baek  to  the  model,  and  fer- 
ret out  the  discrepancy.  If  our  model 
is  fair,  and  we  are  as  particular  as  we 
should  be,. the  variation  from  the  spots 
would  not  exr  ed  one  quarter  of  an 
inch  on  any  kit  of  the  tables  thus 
taken  from  ti,    model. 

The  end'v  *  of  the  frames  in  the 
body-plan  is  'recisely  the  same  as  that 
of  the  half-!  eadth;  the  compasses  are 
set  to  the  thickness  of  the  plank,  and 
one  leg  placed  in  the  corner  where  the 
base  and  -  side'  mes  cross  each  other. 
The  second  leg  is  placed  on  the  side- 
line below,  arid  a  quarter  circle  swept 
from  the  b  *  Mine  inward,  the  com- 
passes tinmng  on  the  lower  leg  be- 
low the  b  e-line.  It  will  be  remem- 
bered that  the  rabbet  swept  on  the 
stem  and  stern-post  was  somewhat  less 
than  the  actual  thickness  of  the  plank  ; 
but  we  are  now  on  the  bottom  of  the 
ship,  or  on  the  side  of  the  keel :  the 
rabbet  here  may  be  swept  to  the  full 
thickness  of  the  plank,  and  extend  the 
whole  length  of  the  straight  rabbet  for- 


ward, and  within  a  few  feet  of  the  post 
aft.  It  is  assumed  that  the  keel  is  of 
parallel  thickness,  consequently  but  one 
sweep  is  necessary  for  the  ending  all 
the  square  frames  in  the  after-body. 

We  now  have  spots  for-  the  battens 
in  the  body-plan,  on  all  the  lines  from 
the  rail  to  the  rabbet,  on  the  keel,  and 
the  battens  must  end  on  the  sweep  made 
for  the  rabbet ;  and  if  we  are  particular 
we  will  discover  that  as  we  go  aft  the 
frames  rise  with  regularity  on  the  side- 
line above  the  base,  and  those  risings 
furnish  the  settings  off"  for  the  continu- 
ation of  the  bearding-line  below  the 
first  water-line,  both  forward  and  aft, 
and  will  be  found  to  agree  as  far  as  the 
frames  may  extend. 

Our  remarks  in  relation  to  the  ex- 
tent of  the  square-frames  do  not  affect 
our  present  arrangements  in  the  ending 
of  the  frames  to  prove  the  lines ;  and 
although  we  have  designated  the  space 
allotted  for  the  cants  in  Plate  3,  Sec- 
tions 1  and  2,  yet  we  have  continued 
the  square-frames,  as  shown  by  the 
dotted  lines,  to  the  extremities  of  the 
ship  ;  consequently,  those  frames,  al- 
though not  intended  to  delineate  the 
shape  of  moulds,  are  taken  off  the  mo- 
del, and  set  off  on  the  floor  in  the 
same  manner  in  which  other  square 
frames  are  ;  they  end  on  the  sweep 
also,  in  like;  manner,  and  their  intersec- 
tion   with    the  side-line  furnishes    the 


132 


MARINE    AND    NAVAL    ARCHITECTURE, 


distance  from  that  point  to  the  base- 
line, which  is  also  the  distance  on  the 
same  frame  from  the  base  to  the  beard- 
ing-line.  By  thus  ending  the  frames 
on  the  sweep,  we  retain  an  equalized 
rabbet,  and  a  straight  garboard  seam, 
if  we  choose  to  adopt  it.  Where  the 
keel  tapers  in  thickness,  which  is  some- 
times the  case  in  smaller  vessels,  we 
require  a  new  side-line  for  every  frame 
coming  over  the  tapered  part,  as  it  is 
plain  that  the  side-line  showing  the 
side  of  the  keel,  or  the  sides  of  the  stem 
and  stern-posts  respectively,  must  be 
directly  over,  or  at  the  part  it  repre- 
sents. This  remark  applies  also  to 
a  rise  of  the  stem  and  keel ;  the  <£> 
frame  being  the  lowest,  it  follows  that 
the  base-line  and  rabbet-sweeps  must 
rise  as  we  advance  either  forward  or 
aft.  We  shall  give  a  fuller  exposition 
of  this  part  of  the  operation  when  we 
shall  have  advanced  as  far  as  the  cants, 
with  which,  at  present,  we  have  nothing 
to  do. 

We  will  now  renew  the  work : — the 
battens,  we  will  assume,  are  tacked  to 
the  frames  in  the  body-plan,  and  to  the 
water  and  sheer-lines  in  the  half- 
breadth-plan  ;  the  heights  have  been 
swept  in  the  sheer-plan,  and  if  the  ho- 
rizontal lines  in  the  body-plan  have 
been  taken  correctly,  and  the  breadths, 
as  shown  by  the  battens  in  the  half- 
breadth  plan,  correspond  with  those  of 


the  body-plan,  and  are  both  fair,  they 
are  correct,  and  may  be  marked  with 
a  thin  piece  of  white  chalk,  in  the  half- 
breadth  plan  ;  and  we  may  here  re- 
mark, that  some  care  is  requisite  in 
marking  the  lines  as  well  as  correcting 
them.  As  soon  as  the  lines  are  mark- 
ed the  battens  should  be  released  from 
their  curved  position,  on  account  of 
their  tendency  to  retain  part  of  the 
curve  or  lose  their  elasticity;  and  while 
upon  this  subject  we  will  add,  that  the 
battens  should  never  remain  from  one 
day  until  the  next  tacked  to  any  con- 
siderable curve  or  line,  if  we  expect  to 
use  them  for  a  similar  purpose  a  second 
time. 

We  may  now  proceed  in  the  same 
manner  with  the  water-lines,  marking 
them  within  a  few  feet  of  their  ends, 
and  after  removing  the  battens,  taking 
a  shorter  batten  and  carrying  out  each 
line  to  its  proper  termination,  or  to  the 
sweep  belonging  to  said  line  ;  and  in 
accordance  with  our  determination  in 
relation  to  the  parallel  or  tapered  stern- 
post,  siding  ways,  the  frames  may  also 
be  marked  in  the  body-plan  tempora- 
rily. We  may  now  determine  the  size 
required  for  the  stern-post,  assuming  it 
to  be  placed  inside-  of  the  ship — we 
have  the  ending  of  the  water-lines,  and 
along  for  several  feet  forward  of  those 
endings,  we  may  place  a  batten  to  the 
thickness  of  the  plank   from   the  line, 


MM 


MARINE    AND    NAVAL    ARCHITECTURE. 


133 


and  parallel  to  the  same,  marking  the 
line,  and  proceeding  to  the  next,  and 
continue  until  all  the  water-lines  are 
thus  circumscribed  by  an  outside  line, 
the  space  between  equalling  the  thick- 
ness of  the  plank,  or  the  depth  the  rab- 
bet on  the  post  is  designed  to  be. 

Having  extended  this  operation  as 
high  as  the  load-line  of  flotation,  we 
may  now  inquire  the  size  of  the  post 
on  the  after-edge.  If  we  follow  the 
leadings  of  the  keel,  we  would  have  it 
the  same  size  as  the  keel,  but  as  it  is 
the  usual  custom  to  taper  the  after-end 
of  the  keel,  we  may  follow  the  prac- 
tice of  the  age,  when  nothing  will  be 
lost  by  so  doing. 

We  shall  now  find  it  necessary  to 
assume  such  dimensions  for  the  aft 
edge  of  the  post  as  correspond  with 
those  before  us,  and  with  the  dictates 
of  our  judgment,  half  of  which  may 
be  set  off  and  lined  aft  of  the  margin- 
line  of  the  post.  This  opening,  or  space, 
shows  half  of  the  stern-post  on  the  af- 
ter side,  and  the  lines  may  be  brought 
to  agree,  if  there  should  be  variations 
between  the  load-line  and  the  base-line, 
as  the  size  of  the  post  is  mainly  deter- 
riiined  by  the  ending  of  the  same. 

The  amount  we  may  deem  it  neces- 
sary to  reduce  the  post  below  the  size 
of  the  keel,  at  the  base-line,  will  also 
determine  the  increased  size  of  the  post 
above  that    of  the   keel,  an   equal  dis- 


tance above  load-line,  with  that  of  the 
base  below  the  load-line — hence,  we 
shall  at  once  discover,  that  to  make  the 
post  on  the  aft  edge,  about  the  same 
size  as  the  siding  size  of  the  keel,  will 
be  a  near  approximation  to  the  pro- 
portionate dimensions. 

The  cross-seam  being  nearer  the 
load-line  than  the  base,  or  the  space 
being  shorter  between  the  load-line  and 
cross-seam,  than  between  the  load-line 
and  base-line,  it  follows  that  the  post 
would  not  be  as  much  larger  at  the 
cross-seam,  than  at  load-line,  as  it  was 
smaller  than  load-line  at  the  base. 

It  will  be  quite  manifest,  that  the 
moulding  side  of  the  post  outside  of  the 
rabbet,  will  be  determined  by  the  thick- 
ness of  the  post  on  the  after-edge  ;  and 
in  order  to  harmonize  those  parts,  we 
should  first  determine  how  much  face 
of  post  we  require  between  the  wood- 
ends  and  the  aft  edge  ;  and  next,  how 
much  the  post  will  side  by  measuring 
the  piece  of  which  it  is  to  be  made, 
the  largest  part  of  which  is  about  the 
load-line,  and  at  the  edge  of  the  rabbet. 
If  we  find  the  post  is  not  large  enough 
to  work  by  those  dimensions,  we  may 
line  the  rabbet  farther  aft,  and  the  edge 
of  the  post  also  farther  aft.  This,  of 
course,  reduces  the  size  of  the  post 
above  water,  and  at  its  surface,  and  as 
a  consequence,  the  siding  size  of  the 
rudder;   but  we   must    remember   that 


134 


MARINE    AND    NAVAL    ARCHITECTURE. 


we  require  but  little  more  than  half 
and  in  some  eases  not  half)  the  rud- 
der that  we  require  under  the  present 
practice. 

It  is  not  important  that  the  bearding 
of  the  post  should  continue  to  follow 
the  angle  of  the  lines  above  the  load- 
line  of  flotation  ;  it  may  gradually  fall 
into  the  parallel  siding  above,  or  be 
ear ried  up  by  the  same  angle  as  that 
at  load-line.  We  should  bear  in  mind, 
that  as  we  require  much  less  exposed 
siding  surface  to  the  post  at  the  head, 
than  at  the  heel,  the  strain  arising  from 
the  caulking  being  in  another  direc- 
tion, and  not  wholly  dependent  upon 
the  same  means  for  support,  (the  fast- 
ening through  the  post  aiding  mate- 
rially.) we  need  take  no  more  than  is 
necessary ;  by  carrying  the  edge  of 
the  rabbet  aft,  at  the  head  and  forward, 
at  the  heel  a  smaller  piece  of  timber 
will  make  the  post. 

Having  arranged  the  ending  of  the 
lines  for  the  post,  we  may  now  carry 
any  alterations  that  may  have  been 
made  in  consequence  of  the  change,  to 
the  body-plan,  and  if  the  alterations 
continue  to  make  a  fair  frame  with  a 
new  ending  for  the  keel,  if  required, 
we  may  regard  the  half-breadth  and 
body  plans  of  the  after-body  as  having 
passed  through  the  first  proof  test  of 
their  correctness,  and  we  may  now  re- 
gulate  the   bearding-line   in  the  sheer- 


plan,  making  it  to  correspond  with  the 
alterations  in  the  half-breadth  ;  to  do 
this,  it  will  be  necessary  to  determine 
the  size  of  post  forward  of  the  rabbet. 
These  dimensions  are  not  arbitrary  : 
that  is  to  say — the  post  need  not  ot 
necessity  come  to  any  definite  distance 
from  the  rabbet,  or  to  any  positive  an- 
gle of  rake  ;  if  the  post  will  work  large. 
make  it  what  it  will  work — the  more 
of  post  we  have,  the  less  of  other  tim- 
ber will  be  required  as  dead  wood  to 
cover  the  heels  of  the  cants,  and  the 
additional  size  also  renders  the  post 
still  more  secure.  That  part  of  the 
stern-post  inside  of  the  rabbet  may  be 
sided  to  the  size  of  the  keel,  in  which 
case  there  would  be  no  alteration  re- 
quired, from  the  former  arrangement 
in  defining  the  bearding-line,  as  the 
dead  wood  would  be  sided  to  the  same 
size ;  but  should  we  taper  the  inner 
part  of  the  post,  by  making  it  larger  at 
the  head  than  at  the  heel,  the  dead 
wood  would  require  to  be  of  the  same 
dimensions,  not  only  at  the  joint  where 
the  post  and  dead  wood  meet,  but  the 
same  sizes  must  be  continued  parallel 
to  the  base-line ;  that  is  to  say — what 
the  size  of  the  fore-side  of  the  post  is, 
four  feet  above  the  base-line,  that  must 
be  the  size  of  the  after  dead  wood,  its 
whole  length  four  feet  above  base,  and 
so  of  any  other  height. 

When  the  post  and  dead  wood  taper, 


MARTNE   AND    NAVAL    ARCHITECTURE. 


135 


the  half  thickness  must  be  taken  at 
every  water-line  in  the  following  man- 
ner :  first,  by  striking  diminishing-lines 
the  length  of  the  post,  the  space  be- 
tween them  being  half  its  siding  size  on 
the  forward  edge.  This  may  be  shown 
on  the  aft  side  of  the  post;  the  line 
showing  the  half  size  of  the  aft  edge 
will  also  form  one  of  the  lines,  and  the 
other  will  come  abaft  the  first;  the  water 
lines  crossing  those  lines  at  their  pro- 
per heights,  will  show  the  half  thick- 
ness at  those  points,  which  must  be 
set  oft"  from  the  middle-line,  and  lined 
parallel  to  the  middle-line  for  a  side- 
line. Where  those  new  side-lines  cross 
their  respective  water-lines  in  the  half- 
breadth,  there  is  found  the  spot  for  the 
bearding-line  in  the  sheer-plan ;  and 
those  spots  or  crossings  may  be  squared 
up  to  their  respective  water-lines,  when 
the  bearding-line  may  be  swept  in  by 
those  spots.  But  another  alteration  is 
consequent  upon  a  tapered  dead  wood  : 
at  the  ending  of  the  frames  on  the  dead 
wood  their  heels  rise  successively  above 
each  other;  hence  it  is  plain  that  the 
farther  aft  the  frame  the  higher  it  ends, 
and  the  higher  the  frame  ends  on  the 
dead  wood,  the  thicker  the  dead  wood 
is  found  to  be,  and  consequently  this 
extra  thickness  must  be  taken  off  the 
frame.  But  this  apparent  difficulty  is 
at  once  reconciled,  by  showing  the  half 
size  of  the  inside  of  the  post  in  the  body- 


plan  in  addition  to,  or  without  the  out- 
side size  of  the  post  in  the  body-plan, 
as  in  Plate  5.  This  side-line,  it  will  be 
seen,  is  not  parallel  to  the  middle-line, 
but  shows  the  size  of  the  post  at  dif- 
ferent heights  ;  hence  it  is  plain,  that 
no  matter  where  a  frame  may  termi- 
nate or  intersect  the  side-line,  it  at  once 
shows  not  only  a  correct  ending  for  the 
frame,  but  the  correct  side-line  for  the 
heels  of  the  square  frames  or  cants,  as 
the  case  may  be.  We  next  come  to 
the  ending  of  the  sheer-lines  of  the  af- 
ter-body ;  we  have  already  shown  that 
the  line  representing  the  stern  in  the 
sheer-plan,  is  at  the  centre  ;  hence  it 
is  plain  that  the  lines  do  not  end  there. 
Few  ship-builders  have  direct  reference 
to  the  model  when  building  the  stern  of 
a  ship,  or  that  part  of  the  stern  above 
the  main  transom  ;  they  may  make  the 
centre  of  the  stern  to  correspond  with 
the  model,  and  this  is  about  all ;  they 
in  general  have  moulds  of  a  few  of  the 
prominent  parts  of  the  stern,  and  make 
all  shaped  ships  in  other  respects  tend 
to  this  shape,  or  to  these  moulds. 

The  same  remarks  will  apply  to  the 
head,  and  this  is  doubtless  the  principal 
reason  why  so  small  a  portion  of  the 
stern  finds  a  place  among  the  illustra- 
tions on  the  floor.  We  cannot  discover 
any  reasons  why  the  model  of  a  ship  will 
not  delineate  at  least  the  shape  of  the 
stern,  as  well  as  the  rake  of  the  same, 


136 


MARINE    AND    NAVAL    ARCHITECTURE, 


at  the  centre  only.  If  Ave  will  take 
the  trouble  to  shape  the  stern  on  the 
model  to  please  our  fancy,  or  il*  we 
prefer  the  beaten  track  of  our  neighbor, 
we  may  show  either,  upon  the  floor, 
with  the  same  degree  of  exactness  that 
characterizes  any  other  part  of  the 
ship.  First,  divide  the  stern  of  the 
model,  or  the  after-body-plan,  into  near- 
ly equal  parts  from  the  middle-line,  and 
strike  lines  from  the  ©  frame  in  the 
body-plan  to  the  rail  of  the  same,  paral- 
lel to  the  middle-line,  as  in  Plate  5  ; 
these  lines  are  called  section-lines,  and 
arc  usually  extended  no  higher  than 
the  cross-seam ;  we  may  now  set  a 
gauge  to  the  size  by  the  scale  repre- 
sented on  the  floor,  from  the  middle- 
line  to  the  first  of  these  lines  called  the 
first  section-line  ;  run  this  gauge-mark 
on  the  stern  of  the  model,  and  the  sec- 
ond and  third  sections  in  like  manner ; 
these  gauge-marks  need  not  extend  be- 
low the  cross-seam  on  the  model ;  any 
other  marks  will  answer  as  well  as 
those,  and  the  reasons  for  recommend- 
ing them  were  that  they  were  more  ea- 
sily made,  and  more  likely  to  be  correct 
than  the  course  commonly  pursued, 
particularly  if  the  stern  has  any  con- 
siderable round  and  twist.  Assuming 
the  model  to  be  separated,  we  may  now 
take  the  distance  within  a  square,  of 
the  first,  second  and  third  section-lines, 
on  the  upper  sheer-piece ;  this  may  be 


done  by  applying  the  stock  of  a  square 
to  the  middle-line,  and  the  tongue 
across  the  model,  the;  edge  of  which  is 
held  to  the  section-line,  and  the  distance 
measured  from  the  edge  of  the  square 
to  the  centre  of  the  stern  on  the  mid- 
dle-line, by  the  same  scale  upon  which 
the  model  is  made ;  these  distances 
must  be  set  off  in  the  sheer-plan,  and 
on  the  same  sheer-line  on  which  they 
Merc  taken,  and  in  the  following  man- 
ner:  apply  the  rule  on  the  sheer-line, 
and  mark  successively  the  distances 
from  the  centre  of  the  stern  to  each 
section-line  forward  of  the  centre;  the 
outside  corner  must  be  also  taken  in 
the  same  manner.  The  process  of 
taking  off  those  stern-sections  is  alike 
on  every  sheer-line,  as  also  that  of  the 
corner,  as  represented  in  Plate  3,  Sec- 
tion 2 — it  must  be  remembered  that 
this  only  applies  to  what  is  called  a 
square-stern  vessel.  Thus  we  discover, 
that  not  only  the  round  of  the  stern 
may  be  shown,  but  the  twist  may  be 
also  shown,  and  by  running  in  other 
extra  sheer-lines,  extending  a  few 
frames  forward,  we  may  not  only  show 
the  true  sweep  of  any  part  of  the  stern, 
but  the  shape  of  the  corner-counter 
timber.  To  determine  the  shape  of  the 
cross-seam,  we  may  take  the  height 
from  load-line  on  the  model  to  the  cross- 
seain  on  the  several  section-lines,  and 
set  them  oft*  in  the  sheer-plan  ;  we  may 


MARINE    AND    NAVAL    ARCHITECTURE. 


137 


also  apply  a  square  to  the  cross-seam 
from  the  middle-line,  to  discover  whether 
the  after-side  is  at  right  angles  with  the 
middle-line  at  the  several  sections  ;  if 
it  is  square  from  the  middle-line  at  all 
the  sections,  the  spots  already  made 
will  rise  ahove  each  other  as  much  as 
the  cross-seam  rises  at  the  respective 
section-lines,  as  shown  in  the  body-plan, 
Plate  5.  We  may  also  strike  those 
parallel  lines  called  sections  in  the 
half-breadth  plan,  making-  the  spaces 
to  correspond  with  those  of  the  body- 
plan,  being  also  the  same  section-lines 
which  can  be  seen  in  the  three  plans, 
viz. :  sheer,  half-breadth,  and  body- 
plan. 

Having  now  the  section-lines  shown 
on  the  stern,  their  intersection  with  the 
cross-seam  may  be    squared  down    to 
the   half-breadth  plan,  and  the  corner 
of  the  stern,  which  is  the  ending  of  the 
sheer-lines,  and  may  be  swept  in,  as  seen 
in  Plate  4  ;  this  line  will  show  the  shape 
of  the   corner  or    margin-line   on  the 
rake  of  the  stern,  and  we   may  obtain 
the  vertical  cross-seam-line  by  squaring 
the  margin-line  down   from  the  sheer- 
line  across  the   half-breadth,  and  take 
the  breadths  and  heights  as  we  would 
in  running  in  a  square  frame    in    the 
body-plan,  where    it    may    be    shown. 
Should  there  be  any  difficulty  found  in 
securing  spots  on  the  corner  to  cany 
the  sweep  from  the  cross-seam  to  the 


rail,  it  may  be  well  to  run  in  one  or  two 
more  section-lines  at  the  parts  where 
the  spots  are  required,  and  obtain 
breadths  and  heights  in  the  same  man- 
ner as  before.  We  may  find  a  ready 
mode  of  arriving  at  the  most  difficult 
parts  of  the  operation  by  extending  the 
gauge-marks  representing  the  section- 
lines  forward  on  each  sheer-piece  ;  we 
may  then  measure  the  distance  from 
any  one  of  the  frames  to  the  edge  of 
the  sheer-piece  on  the  section-line,  and 
apply  the  measurement  to  the  same 
section,  and  from  the  same  frame  from 
which  it  was  taken  in  the  half-breadth 
plan  ;  those  spots  squared  up  to  the 
sheer-plan  will  furnish  additional  data 
in  proving*  the  section-lines,  as  they  are 
usually  taken  from  the  body-plan  and 
applied  to  the  sheer-plan,  as  may  be 
seen  in  Plate  5,  by  taking  the  height 
on  the  section-line  from  the  base  to 
the  successive  frames,  as  they  rise  above 
each  other  ;  this  may  be  done  by  the 
application  of  a  batten?  with  one  edge 
applied  to  the  section-line,  and  the 
square  end  at  the  base,  when  the  sev- 
eral frames  may  be  marked  on  the  edge 
of  the  batten,  and  the  batten  then  ear- 
ned to  the  sheer-plan,  and  applied  suc- 
cessively to  the  frames,  and  the  spots 
marked  on  its  proper  frame;  this  being 
done,  a  batten  may  be  tacked  to  the 
spots,  and  the  line  marked  on  the  floor. 
If  the  cross-seam,  which  is  usually  called 

18 


13S 


MARINE    AND    NAVAL    ARCHITECTURE. 


the  hack  or  after-side  of  the  transom, 
be  square  from  the  middle-line  trans- 
versely, (which  is  readily   ascertained 
by  applying  a  square  to  the  model,)  as 
far  out  as  the  section-lines  extend,  the 
ending   of  those  lines    as    far    as    the 
cross-seam  is  found  to  be  square,  will 
be  at  and   on  the  same  point  at  the 
base  of  the  counter  when  the  stern  is 
of  the  usual   form  ;  but  as  we    have 
shown  in   Plate  4,  they  should  extend 
to  the  rail,  and  define  the  round  of  the 
stern  also.    When  the  cross-seam  leaves 
the  square  or  right-angled-line  from  the 
middle-line  running    forward,  and    we 
have   no  sheer-line  at  that  height,  we 
may  strike  a  perpendicular  line  square 
from   the   base-line    to  the  rail-height, 
and  then  take  measurements  from  the 
model,  by  first   applying  a  square  with 
the  stock  in  a  longitudinal  direction  on 
the  middle-line,  to  obtain  its  round  for- 
ward at  the  several  sections,  and  next 
with  the  stock  of  the  square   in   a  ver- 
tical direction,  to  obtain  its  rise  above 
a  level  or    horizontal  line  ;   the  round 
forward  may  be  set  off  from  this  new 
perpendicular  at  the  section  on  which 
it  was  taken   in   the   half-breadth  plan. 
This  method  differs  only  from  the  one 
before  described,  in  that  of  measuring 
from  aft  in  the   latter  case,  and  from 
forward  in  the  former.      The  latter  can 
be  adopted  when   the   former   cannot. 
Temporary  sheer-lines  may  be  run  in 


the  sheer-plan,  and  the  heights  trans- 
ferred to  the  body-plan,  from  which 
half-breadths  may  be  taken  and  set  off 
in  the  half-breadth-plan,  crossing  as 
many  frames  as  may  be  necessary  to 
regulate  any  particular  part  of  the 
quarter,  buttock,  or  corner  of  the  stern  : 
but  if  proper  attention  is  paid  to  the- 
distribution  of  lines  when  making  mo- 
dels, this  will  rarely  be  required,  as  no" 
part  of  the  model  is  unapproachable 
when  separated,  if  the  lines  have  been 
properly  distributed.  Section-lines  an- 
swer other  purposes  than  the  regula- 
ting of  the  round  of  the  stern,  as  we 
shall  show  in  its  proper  place  ;  they 
are  important  in  laying  down  and  bev- 
elling the  transoms,  proving,  cants, 
&c. 

We  have  doubtless  remained  suffi 
ciently  long  on  the  after-body  to  elu- 
cidate the  manner  of  transferring  its 
shape  to  the  floor,  and  of  subjecting  it 
to  a  first  proof  through  the  aid  of  the 
body-plan.  We  shall  not  pursue  the 
course  of  many  builders  in  carrying  this 
body  through  a  second  proof,  and  com- 
mence making  moulds  before  laying  off 
the  fore-body  as  a  collateral  proof;  we 
believe,  also,  that  diagonal  lines  can  be 
struck  in  both  bodies  to  better  advantage 
than  in  one  alone, and  as  they  determine 
not  only  the  correctness  of  the  work, 
but  the  bevelling  spots,  and  to  some 
extent,  the  length   of  the  timbers,  we  ? 


MARINE    AND    NAVAL    ARCHITECTURE. 


139 


deem  it  most  proper  to  expand  the 
whole  ship,  and  carry  the  fore-body 
through  the  same  operations  the  after- 
body has  undergone,  before  commen- 
cing the  second  proof  with  diagonal 
lines.  We  have  already  shown,  that 
the  same  frames  represent  both  bodies, 
and  having  completed  the  sheer-plan 
in  the  fore-body,  shall  at  once  proceed 
to  laying  off  a  half-body-plan,  and  to 
sweeping  in  the  water  and  sheer-lines, 
which  are  supposed  to  have  been  al- 
ready set  off  in  the  half-breadth-plan 
in  the  same  manner  as  in  the  after-body; 
the  half-body-plan  will  also  be  projected 
on  the  floor  in  the  same  manner  as  that 
of  the  after-body,  and  the  battens  tack- 
ed to  the  lines  in  both  the  half-breadth 
and  body-plan  as  before.  It  will  be  re- 
membered, the  lap  must  be  taken  from 
the  lines  of  the  after-body  ;  that  is, 
the  widths  of  the  frames  29  and  <S>  must 
be  taken  from  the  half-breadth,  (where 
the  frames  are  numbered  below  the 
base-line,)  and  set  off  29  on  its  proper 
frame  aft,  which  is  69,  as  in  Plate  3,  and 
®  would  come  on  frame  73  ;  were  that 
frame  struck  in  the  half-breadth-plan, 
we  shall  now  be  able  to  determine 
whether  the  two  bodies  agree.  If  the 
lap  can  remain  without  any  material 
departure  from  the  spots  taken  from 
tin;  tables,  it  is  best  to  make  the  fore- 
body  agree,  or  to  adjust  the  fore-body 
to  the  lap;  but  if  in  so  doing,  we  must 


alter  to  any  considerable  extent,  it  is 
best  to  extend  a  part  of  the  variations 
to  the  lap,  and  in  doing  so,  we  may  ap- 
ply a  batten  to  those  frames  found  on 
the  lap  in  the  after-body  ;  this  will  as- 
sist us  in  the  adjustment ;  the  heights 
must  also  be  taken  from  the  sheer-plan 
in  the  same  manner  as  directed  in  tin; 
after-body,  and  set  up  as  taken  from 
load-line  in  the  body-plan  ;  level  lines 
being  stricken  across  the  plan  on  which 
the  respective  breadths  must  be  set 
off;  the  battens  in  the  body-plan  being- 
tacked  to  correspond  with  the  halt- 
breadth-plan,  and  both  being  fair;  the 
alteration  on  the  lap  making  a  fair 
frame  in  the  body-plan  of  the  after-body, 
we  may  venture  to  mark  in  the  lines 
with  white  chalk  as  before,  and  remove 
the  battens.  Section-lines  may  be  run 
in  the  fore-body  in  the  same  manner  as 
in  the  after-body ;  but  they  are  not 
often  found  to  be  necessary  in  the  fore- 
body,  and  are  not  always  marked  on 
the  floor  ;  they  may,  however,  be  con- 
tinued the  entire  length  of  the  ship  at 
their  location,  as  we  have  shown,  from 
the  taffrel-rail,  as  in  Plate  4,  to  the 
main-rail  forward.  It  will  be  observed 
that  the  heights  rise  in  regular  succes- 
sion in  the  body-plan,  and  if  a  small 
batten  were  applied  to  the  several  spots 
showing  the  breadths  and  heights,  it 
would  form  a  fair  curve,  as  in  Section 
4,  Plate  2,  or  as  in  Plate  5.     This  may 


140 


MARTNE   AND    NAVAL    ARCHITECTURE. 


be  done  in  both  body-plans,  but  should 
be  done  with  great  care,  as  the  regu- 
larity of  the  sheer  or  sir  marks  depend 
in  some  measure  upon  the  accuracy  of 
the  curve  ;  this  course  may  be  pursued 
on  all  the  sheers  and  the  ending,  or 
the  heights  of  each  sheer  on  the  side- 
line  in  the  sheer-plan,  will  be  the  height 
on  the  side-line  in  the  body-plan  for- 
ward ;  the  sheers  aft  above  the  cross- 
seam  must  be  taken  dh  the  corner  of 
the  stern,  and  not  on  the  centre.  Hav- 
ing swept  in  those  sheers,  we  have  not 
only  the  height  of  every  fourth  frame, 
but  we  have  the  height  of  every  frame, 
as  all  the  frames  cross  those  sheer-lines, 
and  as  a  consequence,  the  point  of  in- 
tersection is  not  only  the  height  of  the 
sheer  on  that  frame,  but  the  half- 
breadth  also  of  the  frame.  Where  dis- 
crepancies are  found  to  exist  in  proving 
those  heights,  which  it  is  not  necessary 
to  do,  it  will  always  be  found  that  there 
has  been  carelessness  somewhere ;  in 
setting  off  the  heights  of  the  sheer  in 
the  body-plan,  each  sheer-line  should  be 
set  off  independent  of  the  other,  and 
all  from  the  same  point,  then,  in  case 
there  should  be  a  mistake  in  one  height. 
the  remaining  sheers  would  not  be  like- 
ly to  have  the  same  error. 

Having  now  expanded  the  vessel 
from  the  model  to  its  full  size  on  the 
floor,  and  lined  up  all  the  frames  from 
base-line  to  rail,  we  will  leave  the  floor 


for  the  purpose  of  endeavoring  to  eluci- 
date the  subject  of  sheering  vessels  more 
fully  than  we  have  yet  done.  By  many 
the  shape  of  the  sheer  of  a  ship  is 
thought  to  be  of  little  consequence,  so 
long  as  there  are  no  irregularities;  in 
other  words,  if  it  is  only  fair,  it  is  quite 
enough. 

By  close  attention  to  this  matter  for 
years,  we  can  come  to  but  one  conclu- 
sion, viz.:  That  in  addition  to  that  of 
the  strength  of  vessels,  very  much  de- 
pends upon  the  sheer  for  appearance. 

The  very  best  modelled  vessel  may 
be  made  to  appear  like  a  mere  hulk  by 
the  manner  of  setting  the  sheer.  It  is 
a  Aery  common  practice  to  set  the  sev- 
eral sheers  parallel  to  each  other,  by 
which  means  the  vessel  is  made  to  bear 
an  aspect  of  sameness  that  is  every 
where  repudiated  by  men  of  taste ; 
again,  we  find  the  sheer  of  ships  regu- 
lated on  the  principle  of  an  inverted 
arch ;  by  either  of  those  modes  we 
make  the  vessel  loom  up  to  her  full 
size.  One  of  the  great  secrets  in  build- 
ing vessels  is  to  make  a  large  vessel 
look  small;  it  is  a  rare  quality,  possessed 
by  few,  and  is  the  only  index  furnished 
by  nature  to  good  proportions,  and 
wherever  found,is  at  once  recognized 
by  even  the  back-woodsman  if  he  has 
studied  nature's  mechanism.  There  is 
something  impressive  in  the  appearance 
of  vessels  to  the  man  who  can  burst 


MARINE    AND    NAVAL    ARCHITECTURE 


141 


the  bands  of  prejudice,  and  launch  out 
on  the  ocean  of  nature  ;  his  first  im- 
pressions are  strong-,  and  very  generally 
correct,  he  will  discover  something- 
wrong,  but  may  be  unable  to  tell  what 
it  is,  he  looks  at  her  shape,  she  tapers 
at  both  ends  ;  the  strakes  of  plank  like- 
wise taper ;  the  spars  grow  smaller  at 
the  extremities;  in  a  word,  he  inquires 
in  his  own  mind,  has  not  this  been  the 
governing  principle  in  the  construc- 
tion of  this  stupendous  fabric  ?  The  im- 
pression still  lingers  that  there  must  be 
a  discrepancy,  or  why  the  impression  ? 
He  still  looks  with  eager  gaze,  when  he 
finally  discovers  that  every  part  of  the 
ship  shows  a  proportionate  reduction 
at  the  extremities — but  those  openings 
between  the  mouldings — the  secret  is 
out ;  he  may  be  no  mechanic,  and,  as 
a  matter  of  course,  will  not  express 
an  opinion,  professing  to  know  little 
about  the  art.  We  are  too  apt  as  me- 
chanics to  look  at  our  work  with  a 
prejudiced  eye,  and  consequently  are 
wholly  unprepared  to  judge  of  its  quali- 
ties. We  would  not  dare  to  touch  this 
subject  had  we  not  resolved  to  cut  to 
the  line,  regardless  of  the  ill-deserved 
censures  we  may  bring  upon  us  by  in- 
terfering with  many  of  the  hereditary 
notions  of  the  aire  in  the  art  of  build- 
ing  ships.  We  have  often  realized  this 
truth,  that  it  were  less  hazardous  to 
disturb  the  person  of  an  individual,  than 


his  prejudices ;  but  having  been  more 
or  less  fortunate  (time  alone  can  de- 
termine which)  in  occupying  a  position 
from  which  we  could  test  the  utility  of 
many  of  the  prominent  features  of  the 
present  time  in  ship-building,  we  have 
spread  our  banner  to  the  breeze  bear- 
ing our  motto  of  fitness  for  the  pur- 
pose, and  proportion  to  effect  the  same. 
One  of  the  grand  objects  originally  in 
sheering  vessels  was  to  gain  an  addi- 
tional amount  of  strength,  by  transfer- 
ring to  some  extent  the  weight  of  the 
ends  on  the  middle  of  the  vessel ;  but  it 
was  found,  that  by  giving  the  ship  sheer 
enough  to  accomplish  this,  we  made  her 
inconvenient  for  those  who  managed 
her,  unless  the  decks  had  less  sheer 
than  the  outside  of  the  ship.  The  ta- 
pered sheer  relieves  us  from  this  diffi- 
culty ;  the  sheer  of  the  wale  docs  not 
affect  the  sheer  of  the  deck;  and  what 
would  be  gained  from  a  rank  sheer 
above  would  be  but  little,  inasmuch  as 
the  top-sides  are  usually  of  lighter  ma- 
terials, on  account  of  the  reduction  of 
weight  above  the  centre  of  gravity, 
which  is  Avorthy  of  consideration.  We 
may  give  the  wale  all  the  sheer  we  de- 
sire, and  reduce  it  on  the  plank-sheer 
to  what  we  want  the  deck  to  have, — 
the  deck,  however,  need  follow  the  out- 
side sheer  no  farther  than  the  fore- 
mast. This  practice  is  very  generally 
adhered  to  in  New  York,  and  with  good 


142 


MARINE    AND    NAVAL    ARCHITECTURE. 


results  ;  for  by  so  doing,  we  are  enabled 
to  obtain  forecastle  room  without  going 
between  decks;  in  addition  to  which, 
we  may  bring  the  hawse-holes  lower, 
which  is  also  an  advantage  ;  the  deck- 
line  may  be  straightened  sufficient- 
ly, and  yet  retain  a  sheer  from  the 
hawse-holes  aft,  provided  the  bow  is 
deeper  than  the  stern,  which  is  an  im- 
portant qualification  in  sea-going  ves- 
sels. By  this  arrangement  we  are  also 
enabled  to  have  a  top-gallant  forecastle 
below  the  rail,  and  find  a  sufficient  safe- 
guard above  in  the  chocks,  that  answers 
a  two-fold  purpose — to  prevent  the  loss 
of  men,  and  serve  as  warping-chocks  as 
tiir  as  required,  which  is  seldom  much 
abaft  the  windlass.  We  mean  by  a  ta- 
pered-slieer,  one  that  when  measured 
vertically  from  another  sheer,  either 
above  or  below,  measures  less  at  the 
ends  than  midships — when  at  the  same 
time  on  the  flare  of  the  bow  the  open- 
ing will  often  measure  more  than  mid- 
ships; but  again,  we  may  have  the 
taper,  and  still  retain  a  heavy  sluggish 
appearance.  There  is  more  life  neces- 
sary to  the  appearance  of  the  bow,  than 
is  required  aft ;  hence  it  is  quite  mani- 
fest, that  we  must  depart  from  the  seg- 
ment of  the  circle  to  obtain  it.  This 
lively  appearance  that  we  sometimes 
see,  which  makes  a  vessel  look  as  though 
she  would  move  without  the  applica- 
tion of  propelling   power,   is  only  ob- 


tained, so  far  as  the  sheer  is  concerned, 
by  making  the  line  quicker  at  the  bow. 
and  less  so  at  the  stern.      There  is  in 
sheering,  as  in  other  things  on  a  ship, 
a  certain   curve  adapted  to  a   certain 
shape  of  vessel ;   this  is   only    another 
name  for  proportions.      The  object  in 
building  ships  is  to  compel  them  by  the 
application  of  power  to  move  forward  : 
and  is  it  not  perfectly   clear  that  every 
effort  in  appearance,  as  well  as  in  other 
things,  should  tend  forward  ]  and  can 
this  be  accomplished  by  sheering  ships 
by  the  curvature  of  the  circle  ?    The  re- 
sponse must  come  from  every  unpre- 
judiced mechanic  in  the  negative.     It 
costs  no  more  to  build  a  ship  to  appear 
to  be  doing  what  she  is  really  designed 
to  do,  than  otherwise;  a  ship  may  have 
a  very  considerable  amount  of  sheer. 
and  yet  not  look  crooked,  provided  she 
is  kept  low  aft.      The  practice  has  been 
adhered  to  every  where,  until  recently 
in  Europe  and  America,  of  making  the 
largest  frame  the  lowest  one,  or  the  ® 
frame  the  lowest  part  of  the  sheer  ;  the 
sheer  at  the  stern  should  not  be  much 
higher  than  its  lowest  part  to  impart 
this  zest   so  important  to  the  appear- 
ance of  ships.     The  wall-sided  floating 
warehouse    requires    a   very   different 
shaped  sheer  from  the  ship  of  thirteen 
knots  by  the  wind.     We  repeat  the  as- 
sertion that  there  is  a  peculiar  shape 
of  curvature  adapted  to  the  sheer  of 


MARINE    AND    NAVAL    ARCHITECTURE. 


143 


every  description  of  vessel,  and  its  shape 
is  admired  or  rejected  almost  at  the  first 
glance  in  the  mind  of  the  observer,  and 
indeed,  it  is  so  designed  by  the  builder, 
when  he  makes  mouldings,  and  colors 
them  to  attract  the  eye  of  the  observer  ; 
and  with  a  sheer  adapted  to  the  form 
of  the  ship,  although  a  mere  box,  as  it 
regards  shape,  will  be  quite  a  passable 
ship  in  appearance. 

We  have  said  that  there  should  be  a 
sheer  adopted  that  would  suit  the  ves- 
sel ;   we  mean  by  this  just  what  we  say, 
as  much  as  if  we  had  said  that  a  coat 
should  be  fitted  to  the  body  of  the  man 
who  is  to  wear  it.     Let  two  ships  be 
built  by  the  same  dimensions,  length, 
breadth,  and  depth   midships,  with  the 
same    difference  in    the    depth    of  the 
bow  and  stern — the  one  longitudinally 
straight-sided,  carrying  her  length  on 
the  side-line  almost  as  far  as  the  cen- 
tre— in  other  Avoids,  let  her  length  be 
nearly  as  great   along   the  side  as  at 
the  centre,  thus  making  a  bow  nearly 
straight   across  from  cat-head  to  cat- 
head— the  second  may  have    an  easy 
side-line,  and  increase  in  length  on  every 
foot  of  the  side-line  to  its  extremity — 
will    it  not   appear   manifest,  that    the 
same  curvature  on  those  two  ships  will 
not  only  appear  to  differ,  but  will  differ 
widely  ;   the  end  of  the  first  ship  seems 
to  be  at  the  cat-head,  while  the  second 
is  several  feet  farther  forward.      On  the 


first  ship  the  effort  is  concentrated  at 
the  cat-head,  while  on  the  second  it  is 
transferred  to  the  stem.  If  the  ship 
first  described  should  have  the  rise  of 
the  sheer  extended  beyond  the  cat-head, 
or  at  the  termination  of  the  straight, 
across  the  bow,  the  whole  bow  will  have 
the  appearance  of  foiling  or  sagging  off. 
This  termination  on  the  other  would 
have  the  opposite  effect;  the  bow  at 
the  stem  would  appear,  as  in  fact  it 
would  be,  below  the  other  sections  of 
the  sheer.  The  subject  will  perhaps 
appear  more  clear,  if  we  were  to  bend  a 
batten  from  the  fore-edge  of  the  knight- 
head  along  the  heads  of  the  timbers  at 
the  lower  side  of  the  rail,  as  for  aft  as 
the  forward  part  of  the  fore-chains, 
where  it  may  be  secured  ;  the  fore-end 
may  now  be  released,  and  carried  out 
until  it  comes  in  line  with  the  side,  or 
in  line  with  its  after-end  ;  with  the  bat- 
ten remaining  in  that  position,  we  shall 
discover,  that  to  raise  the  sheer  the 
whole  length  of  the  batten  in  the  same 
ratio  that  it  is  raised  aft  of  the  luff  of 
the  bow,  would  be  to  lift  the  sheer  above 
the  effort  of  the  bow,  and  deprive  it 
of  the  aid  of  the  sheer  in  centreing 
the  effort  there.  The  most  casual  ob- 
server will  at  once  see  its  effect  :  it 
may  be  seen  on  many  eastern  vessels 
of  smaller  size — brigs  and  schooners. 
These  vessels  are  often  built  by  men 
who  are  not  in  possession  of  the  many 


144 


MARINE    AND    NAVAL    ARCHITECTURE 


advantages  arising'  from  an  apprentice- 
ship, and  consequently  their  vessels  ex- 
hibit a  lack  in  many  of  the  prominent 
features  which  characterize  American 
vessels  generally.  The  whole  frater- 
nity of  New-England  ship-builders  have 
suffered  loss  in  their  reputation  in  con- 
sequence. The  reasons  for  adopting 
this  mode  of  sheering,  is  doubtless  to 
avoid  the  sni  in  planking  and  in  the 
bulwarks  ;  such  vessels  are  an  eye-sore 
to  men  of  taste  ;  but  if  on  the  easy  bow 
this  continued  rise  to  the  extremity  ap- 
pears ludicrous,  how  much  more  so 
would  it  appear  on  the  ship  just  de- 
scribed !  It  will  be  at  once  discovered 
that  she  might  be  considered  a  second 
edition  of  the  Dutch  Galliot,  or  not 
much  ahead  of  the  Chinese  Junk  ; 
hence  it  is  plain  that  a  medium  should 
be  observed  ;  the  sheer  we  set  on  a 
vessel  of  the  same  dimensions  as  the 
galliot,  would  make  her  appear  still 
worse  to  us  than  she  now  does — that 
kind  of  vessel  requiring  more  sheer  in 
proportion  to  the  length  than  a  vessel 
having  easier  lines.  But  although  the 
same  ratio  of  rise  that  characterizes 
the  sheer  from  the  fore-chains  to  the 
luff  of  the  bow,  may  not  be  continued 
to  the  extremity  on  the  full  bow,  nor 
yet  only  in  part  on  the  bow  of  more 
regular  curve  on  the  rail  and  plank- 
sheer,  as  Section  1  of  Plate  3,  it  may 
be  carried  fully  out  on  the  very  sharp 


ocean  or  river  steamer,  as  in  Section  1 
of  Plate  2.  Thus  we  discover,  that 
what  in  the  one  case  would  be  perfect- 
ly absurd,  in  smother  will  be  not  only 
admissible,  but  requisite. 

To  sum  up  all  that  may  be  necessary 
for  us  to  add  upon  the  subject  of  sheer- 
ing, we  may  subjoin  the  following  : — 
The  whole  expression  of  the  sheer 
must  be  concentrated  in  a  single  point. 
The  head  is  the  representative  of  this 
expression  ;  the  tapering  spaces  be- 
tween the  wale  and  plank-sheer,  and 
bulwarks  between  the  plank-sheer  and 
rail,  have  a  tendency  to  draw  all  the 
power  of  effort  to  this  point,  and  as  a 
consequence,  the  effect  is  to  make  her 
appear  like  a  thing  of  life. 

It  may  not  be  out  of  place  to  con- 
sider some  of  the  most  important  dis- 
turbing forces  which  have  a  tendency 
to  cause  a  departure  from  the  shape 
shown  in  the  sheer-plan  of  a  ship ;  a 
part  of  those  forces  are  inherent  in  the 
form  of  the  ship  :  others  are  brought 
into  action  when  the  ship  is  in  motion. 
In  the  first  chapter,  it  has  been  ex- 
plained, that  when  the  ship  is  at  rest  on 
still  water,  the  total  weight  of  the  ves- 
sel is  equal  to  the  upward  pressure  of 
the  water,  but  it  docs  not  necessarily 
follow,  that  the  weight  of  every  portion 
of  the  vessel  shall  be  equal  to  the  up- 
ward pressure  of  that  portion  of  water 
which  is  immediately  beneath  it.      On 


MARINE    AND    NAVAL    ARCHITECTURE. 


145 


the  contrary,  the  shape  of  the  vessel  is 
such,  that  these  weights  and  pressures 
arc  very  unequal,  which  will  appear  if 
we  suppose  a  ship  to  be  divided  into 
sections  of  equal  length  by  vertical  bulk- 
heads. Assuming  the  mean  of  the 
lengths  between  the  load  and  base-lines 
as  the  length  for  division  ;  we  will  also 
assume  these  bulk-heads  to  be  water- 
tight, and  the  sections  to  be  to  a  line 
of  flotation  equivalent  to  their  weight ; 
it  will  be  found  that  the  forward  and 
after  sections  draw  more  water  than 
those  sections  nearer  the  centre,  which 
affords  the  most  conclusive  proof  that 
the  ends  of  the  ship  are  dependent  upon 
the  middle  for  support.  The  bow  must 
of  necessity  sustain  the  greater  portion 
of  this  over-hanging  weight.  Assum- 
ing the  two  bodies  to  be  of  equal  buoy- 
ancy, each  side  of  the  longitudinal  cen- 
tre, (which  may  be  adopted  with  ad- 
vantage on  the  most  burthensome  ves- 
sels,)  the  weight  of  the  bow-sprit, 
anchors,  and  often  a  large  portion  of 
the  chains,  in  addition'  to  increased 
weight  of  the  foremast,  yards,  rigging, 
&c,  over  those  of  the  mizzeri,  requires 
extra  strength  in  this  section  to  prevent 
the  ship  from  hogging  ;  and  when  these 
extra  means  are  neglected,  the  ship  is 
found  to  have  lost  her  original  shape  at 
this  extremity.  The  extra  depth  for- 
ward is  well  calculated  to  counteract 
this  hogging  tendency  found  in  the  for- 


ward section  of  almost  all  description 
of  vessels ;  the  additional  amount  of 
sheer  is  also  an  important  advantage, 
and  an  additional  aid  to  prevent  a  de- 
parture from  the  form  when  built. 

The  careful  observer  will  discover, 
that  this  departure  from  the  original 
shape  commences  at  an  early  period  in 
the  ship's  history — much  earlier  than 
the  casual  observer  had  imagined.  We 
need  not  wait  until  a  large  heavy  ship  is 
launched  before  we  can  discover  a  de- 
parture from  the  original  shape;  unless 
particular  care  is  taken  to  place  the 
keel-blocks  closer  together  forward  and 
aft,  or  the  ends  of  the  keel  are  raised 
above  a  straight  or  fair  line,  we  shall 
find  our  ship  is  (what  is  technically 
called)  hogged  before  she  is  launched. 
The  author  has  seen  more  than  one 
ship  thus  hogged.  The  moment  of 
launching,  however,  is  the  period  when 
the  disturbing  forces  commence  opera- 
ting oii  every  portion  of  the  hull. 

It.  must  be  remembered  that  these 
forces  are  in  almost  constant  activity 
to  destroy  the  connection  between  the 
several  parts  of  the  structure  ;  and 
whatever  working  may  be  produced  by 
their  operation,  tends  very  materially 
to  increase  their  effect,  because  an  in- 
creased momentum  is  acquired  in  their 
action  on  each  other. 


19 


14(5 


MARINE  AND    NAVAL    ARCHITECTURE. 


CHAPTER    V. 

Parallels  to  the  Line  of  Flotation,  commonly  called  Water-Lines — Their  Effect  in  modelling — Half-Breadth 

Plan — Body  Plan — Operations  on  the  Floor  in  Laying  Off. 


Having,  by  our  expositions  from  the 
model,  carried  our  readers  to  the  dis- 
tribution of  the  water-lines  upon  the 
floor,  more  properly  called  parallels  to 
the  line  of  flotation,  as  shown  in,  first, 
the  sheer-plan ;  second,  in  the  half- 
breadth-plan  ;  and  third,  in  the  body- 
plan,  we  shall  next  show  the  manner 
of  doing  the  same  upon  paper.  The 
draught,  all  hough  obsolete  in  Marine 
Architecture  throughout  the  United 
States,  is  yet  adhered  to  by  Naval 
Architects  in  both  the  old  and  new 
worlds.  Before  entering  upon  an  ex- 
position of  this  part  of  construction,  it 
is  necessary  that  we  should  give  some 
practical  illustrations,  which  may  be 
found  useful  in  furnishing  data  for  the 
formation  of  the  vessel  upon  a  plane  ; 
as  the  draught  furnishes  the  beginner 
with  no  index  by  which  to  determine 
the  shape  of  the  vessel,  as  a  conse- 
quence, he  is  quite  in  the  dark  as  to 
the  form  in  its  rotundity,  although  the 
draught  be  before  him.  Thus  it  will 
be  perceived  that  it  is  necessary  to  have 
some   experience   in    a    matter    of  so 


much  moment,  before  we  arc?  prepared 
to  judge  correctly  of  the  shape  when 
spread  out  on  a  plane. 

The  favorite  water-line  does  not  fur- 
nish a  reliable  shape,  as  is  too  generally 
supposed.  Scientific  men  both  in  Eu- 
rope and  America  have  erred  in  as- 
suming that  the  parallel  to  the  line  of 
flotation  was  the  actual  line  of  resist- 
ance. This  mistake  has  not  been 
confined  to  theorists.  Practical  ship- 
builders for  many  years  have  to  a  very 
great  extent  regarded  this  as  an  axiom 
in  the  great  problem  of  resistance;  but 
the  commercial  world,  for  the  first  time 
in  its  history,  has  an  exhibition  of  the 
advantages  of  scientific  and  practical 
knowledge,  when  operating  by  different 
means,  (each  without  the  knowledge 
of  the  other,)  and  arriving  at  nearly 
the  same  results  by  taking  opposite 
courses.  The  theorists  of  England 
have  discovered  something  they  sup- 
pose to  be  tangible  in  relation  to  the 
formations  of  parallels,  as  adequate  to 
the  diminution  of  resistance  on  both 
ends  of  the  vessel ;  in  other  words,  they 


MARINE    AND    NAVAL    ARCHITECTURE. 


147 


have  assumed,  that  were  the  several 
lines  of  flotation  formed  in  accordance 
with  the  formation  of  the  wave,  from 
which  they  have  assumed  the  propriety 
of  calling  it  the  wave-principle — a 
name  not  unworthy  of  its  distinguish- 
ed author,  Mr.  Russell — who  claims 
to  have  discovered  and  experimented 
upon  it,  and  which  may  be  defined  as  a 
mode  of  construction,  taking  its  name 
from  the  phenomena  which  takes  place 
in  the  water,  and  which  are  called 
waves. 

Its  adherents  assume  that  it  may  be 
fairly  expected,  that  he  who  most  near- 
ly imitated  those  perfect  operations  of 
nature,  would  also  most  nearly  ap- 
proach to  that  perfection  which  is 
manifested  in  them.  There  are  vari- 
ous orders  of  these  waves  ;  only  two  of 
which,  however,  act  a  prominent  part 
in  what  is  recognized  as  the  wave- 
principle  of  construction.  The  first  is 
the  wave  of  translation — the  charac- 
teristic of  which  is,  that  it  takes  up  any 
light  body  or  particle,  lifts'  it  gradual- 
ly to  a  certain  height,  and  as  gradu- 
ally lowers  it  again  ;  having  carried  or 
kept  the  body  or  particle  above  the 
level,  from  whence  it  was  taken  the 
entire  length  of  the  wave,  it  stops  while 
the  wave  moves  on — like  as  in  a  field 
of  grain,  the  wheat  remains  in  the 
ground,  but  the  waving  moves  across 
the  field.    Fig.  1,  Plate  6,  will  exhibit  the 


form  of  the  wave  of  translation,  and  also 
show  the  relative  heights  that  a  parti- 
cle is  raised  to  ;  as  each  successive 
part  of  the  wave  passes  a  given  point. 
The  wave  of  oscillation  is  thus  propa- 
gated :  if  a  body  be  moved  fast  through 
the  water,  there  will  be  left  behind  it  a 
partial  vacuum,  which  will  be  filled 
principally  with  the  water  from  beneath 
by  the  removal  of  the  part  of  the  pres- 
sure at  the  surface,  while  that  at  the 
surface  will  be  so  only  by  force  of  the 
water  around,  or  the  contiguous  par- 
ticles, which  force  is  much  less  ;  tin; 
water  then,  which  is  immediately  above 
that  which  is  forced  into  the  vacant 
space,  will  fall,  and  the  consequence 
will  be,  that  an  undulatory  or  oscillating 
motion  will  be  produced  ;  this  motion 
has  been  denominated  a  wave  of  oscil- 
lation, and  is  that  motion  formed  astern 
or  behind  a  vessel  when  she  moves 
ahead.  The  length  of  this  wave,  as  of 
that  of  translation,  depends  on  the  ve- 
locity of  its  propagation,  which  also 
depends  on  the  velocity  of  the  moving 
body.  The  water  being  divergent,  or 
tending  to  various  parts  from  Che  bow, 
it  follows,  that  if  the  acceleration  of  it 
were  continued  by  an  increase  of  pow- 
er on  the  vessel,  it  would  be  found  that 
at  the  termination  of  the  bow,  or  at  the 
aft-side  of  the  luff  of  the  bow.  there 
would  be  a  partial  vacuum  formed,  the 
vessel    would    settle    down    and    draw 


14S 


MARINE    AND    NAVAL    ARCHITECTURE. 


more  water,  the  resistance  would  at 
the  same  time  be  increased,  and  as  a 
consequence,  there  would  be  a  loss  of 
power.  Such,  however,  is  not  the  case 
aft ;  as  the  water  from  the  after-body 
is  convergent,  or  tends  to  one  point,  it 
may  be  accelerated  up  to  the  stern-post 
with  advantage ;  for  the  greater  its 
velocity  there,  the  greater  will  be  its 
reaction,  which  will  be  favorable  to 
the  progress  of  the  vessel,  and  have  a 
tendency  to  give  her  an  onward  thrust 
rather  than  have  a  retarding  influence, 
caused  by  the  vertical  motion  which 
may  be  seen  following  many  vessels  as 
now   built. 

These  waves  are  found  to  vary  in 
length  in  the  ratio  of  their  velocity  as 
tabulated,  which  may  be  found  by  re- 
ference to  any  work  on  the  theory  of 
waves  ;  so  that  when  the  velocity  at 
which  a  vessel  shall  be  driven  is  deter- 
mined, the  length  of  the  bow  will  be 
the  length  of  the  wave  in  the  table 
which  corresponds  to  this  velocity. 
The  length  of  the  wave  of  translation, 
as  compared  with  the  wave  of  oscilla- 
tion, is  as  two  to  three,  but  as  only 
half  of  the  wave  of  oscillation  is  taken, 
and  the  whole  of  the  wave  of  transla- 
tion, so  the  length  of  the  fore-body  as 
compared  with  the  length  of  the  after- 
body, is  as  three  to  two.  Fig.  I,  Plate 
6,  is  a  theoretic  wave-curve  of  a  water- 
line.      The  genesis,    or    formation  of 


these  curves,  is  as  follows:  the  length 
of  the  fore-body  as  compared  with  that 
of  the   after-body,  is  as  three  to  two  ; 
therefore  the  whole  length  of  the  curve 
is   divided    into    five    equal    parts,  and 
three  allotted  to  the  fore-body.     A  cir- 
cle whose  diameter  is  equal  to  the  half- 
breadth  of  the  vessel  on  any  line  of  flo- 
tation, (as  it  seems  to  be  intended  for 
all  the  water-lines,)  is  described   with 
its  circumference  intersecting  the  mid- 
dle-line at  the  junction  of  the  fore  and 
after-body,  as  in  Fig.  1 ;  its  circumfe- 
rence is  divided  into  sixteen  equal  parts, 
and  the  middle  or  straight-line  running 
through  the  centre  of  the  vessel,  is  di- 
vided into  eight  equal  parts.     We  have 
now  eight  spots  on  each  half  of  the  cir- 
cle, and  the  same  number  on  each  end 
or  side  of  the  centre  of  the  circle,  w  liich 
also  shows  the  greatest  transverse  sec- 
tion ;    square    up    these    spots   on    the 
middle-line  from  the  same,  and   strike 
lines    parallel  to   the  same,   extending 
from   each  division  of  the   circle  to  its 
corresponding  division   on  the  middle- 
line,  the  lines  it  will  be  discovered  con- 
tinue to  grow  shorter  as  we   advance 
outward;   the  points  where  the  paral- 
lels cross  the   perpendicular,  are  those 
through  which  a  line  being  drawn  will 
form  the  wave-line  curve  ;   the  curve  of 
all  or  any  water-line  of  any  description 
of  vessel  may  be   formed   in    the   same 
manner.      Fig.   1,  however,  may   only 


MARINE    AND    NAVAL    ARCHITECTURE. 


149 


represent  the  form  for  the  extremities 
of  the  vessel ;  the  middle  may  be  con- 
tinued with  a  more  gentle  curve  to  any 
length. 

The  advantages  of  the  wave-bow  are 
set  forth,  in  the  assumption  that  in- 
stead of  accumulating  the  water  at  the 
stem,  where  its  effect  is  to  give  greater 
support  to  the  ends,  and  as  a  conse- 
quence less  to  the  sides  of  the  vessel ; 
tending  also  to  decrease  the  practical 
stability.  It  accumulates  the  water  at 
the  sides,  and  takes  it  away  from  the 
centre ;  the  effect  of  which  is  to  in- 
crease the  practical  stability  and 
weatherliness,  while  the  old  form,  by 
accumulating  the  water  close  to  the 
stem,  carries  (with  the  wind  a-beam) 
the  resultant,  or  the  effect  of  the  com- 
pound force  of  the  water  much  farther 
forward,  and  therefore  requires  to  have 
the  centre  of  propulsion,  or  the  effort 
of  all  the  sail  farther  forward,  to  coun- 
teract its  evil  effect,  as  we  have  shown 
in  Plate  1  ;  this  again  requires  a  larger 
bowsprit,  and  the  foremast  farther  for- 
ward, which,  by  increasing  the  angle  of 
pitch,  is  injurious  to  the  ship  in  several 
ways.  Another  prominent  feature  in 
the  wave-principle  is,  that  by  bringing 
this  accumulation  aft,  the  centre  of 
resistance  of  the  water  and  the  cen- 
tre of  propulsion,  or  of  the  sails,  are 
brought  more  nearly  into  the  same  ver- 
tical line  or  plane   with  the  centre  of 


gravity, — all  of  which  contributes  to 
economize  power  and  facilitate  quick- 
ness of  turning.  It  may  be  well  to  ob- 
serve that  theory  and  practice  here 
agree.  To  substantiate  the  truth  of 
the  latter  clause  of  the  fore<join°  re- 
mark,  viz.,  that  by  removing  the  great- 
est transverse  section  farther  aft,  and 
relieving  the  bow  of  its  irregular  full- 
ness under  the  cat-head,  we  facilitate 
the  obedience  to  the  helm,  provided  the 
bow  is  also  relieved  of  the  press  of  sail, 
by  arranging  the  masts  a  proportionate 
distance  farther  aft.  Public  opinion, 
however,  is  not  yet  prepared  for  so 
great  an  innovation  into  the  stereo- 
typed  practices  of  the  age,  and  of  course 
repudiates  any  statement  to  that  effect, 
notwithstanding  backed  by  tangible  de- 
monstrations, that  ought  to  settle  the 
matter  in  an  unprejudiced  mind. 

The  adherents  to  the  wave-principle 
also  give  reasons  for  advocating  the 
wave-bow,  by  examining  the  subject 
in  a  manner  divested  of  that  bias  which 
usually  characterizes  the  analytical  ex- 
positions of  the  propagators  of  a  new 
system. 

Suppose,  as  we  have  shown,  Fig.  2, 
Plate  6,  to  represent  the  plan  of  a 
horizontal  section  of  one  side  of  a  bow  : 
it  will  be  seen  that  it  is  divided  by  lines 
perpendicularly  to  the  keel,  and  square 
from  the  middle-line  into  equal  portions, 
and  that  those  perpendiculars  are  drawn 


150 


MARINE    AND    NAVAL    ARCHITECTURE. 


from  the  middle-line  to  the  outline  of 
the  bow,  at  which  intersection  another 
line  is  drawn  from   thence  to  the  next 
perpendicular,  and  parallel  to  the  mid- 
dle-line, and  so  of  all  the  rest.      When 
motion  is  given  to  the  vessel  in  the  di- 
rection   of  her    keel  and    ahead,  each 
section  being  alike  in  length,  it  will  im- 
part to  the  water  it  comes  in  contact 
with,  an  equal  velocity  in  that  direction; 
but  not  only  so,  each  section  will  im- 
part to  the  water  a  velocity  in  a  direc- 
tion perpendicular  to   this,  or  at  right 
angles  with  it,  and  different  in  degree, 
but  in  the  same   ratio    as  their  respec- 
tive   breadths  differ.     As   the   velocity 
in  the  first  direction,  or  in  the  direction 
of  the  keel,  is  the  same  in  amount  for 
each  section,  (they  being-  all  of  a  length 
fore  and  aft,)  it   may  be  disregarded  ; 
but  when  we  consider  the  consequence 
of  the  difference  of  velocities  imparted 
to  the  water,  because  of  their  difference 
of  breadth,  this  velocity  is  very  different 
in  degree,  as  is  evident  from  the  fact, 
that  before  the  water  on  Section  1  can 
move  its  own  length  astern,  and  permit 
the  vessel  to  move  the  same  distance 
ahead,  it  must  push  the  water  out  to  a, 
that  2  may  advance  a  like  space  :  after 
having  pushed   the  water  out  only  the 
distance  2  b,  and  3  by  the  smaller  dis- 
tance 3  c,  and  so  of  the  remaining  sec- 
tions, the   consequence   of  this  will  be 
seen  in  an  accumulation  of  water  prin- 


cipally on  the  first  section,  because  the 
velocities  imparted  by  the  sections  are 
less  in  proportion,  as  they  are  more  dis- 
tant from  No.  1  ;  so  that  the  difficulty 
of  escape  for  the  water  from  any  sec- 
tion is  increased  by  the  accumulation, 
which  arises  from  the    difficulty  of  es- 
cape for  the  water  from  the  following 
sections — 4,  5,  6 — and  so  on  as  may  be; 
therefore  the  accumulation  on  1   will 
be  in  proportion  to  the  velocity  it  im- 
parts, together  with  the    difficulty    of 
escape  for  the  water  arising  from  the 
form  of  the  other  sections ;  and  when 
the   velocity  of  the  vessel  is  great,  this 
accumulation  will  take  place  to  a  great- 
er extent,  and  cannot   be  confined  to 
the  surface  ;   for  if  the  lower  parts  of 
the   bow  are    similarly    formed,  a    like 
process  will  go   on,   differing   only  in 
degree ;  therefore  it  must  be  perfectly 
clear,  that  the  water  from  Section  1 
cannot   flow    out  by   passing  over  the 
water  from  No.  2,  leaving  that  water, 
and  the  water  of  the  following  sections, 
to  act  on,  and  be  acted  upon,  each  by 
its  own  section  ;  for  the  whole  column 
of  Section  1,  including  each  portion  of 
that  column,  would  have  to  rise  above 
each  portion  of  the  column  of  Section 
2,  which  is  impossible;  instead  of  which, 
when  the  vessel  is  going  fast,  a  stream 
flows    outward  from   Section    1,  with 
a  velocity  in  proportion  to    the  accu- 
mulation,  which    will  be   the   greatest 


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MARINE    AND    NAVAL    ARCHITECTURE 


151 


(all  other  things  being  equal)  when  the 
breadth  of  Section  1  is  greatest,  or  when 
the  form  is  fullest  at  that  part ;  and  the 
effect  of  this  current  will  be  to  inter- 
cept and  prevent  the  pressure  of  the 
water  on  the  after-parts  of  the  bow — 
which  would  take  place  were  it  not  for 
this  current. 

The  prominent  objections  have  thus 
been  given  by  the  wave-principle  ad- 
herents to  the  round  bow,  both  at  and 
below  the  line  of  flotation,  from  which 
we  may  readily  perceive  that  (assuming 
the  theory  to  be  a  correct  one)  a  kind 
of  false  or  water-bow  is  found  around 
the  full  irregular  bow,  which  serves  as 
a  regulating  medium  to  adjust  the  diffi- 
culties in  shape,  at  the  expense  of  speed 
and  other  important  qualities.  But 
their  objections  are  no  less  feasible  to 
the  straight  bow,  which  is  deemed  more 
favorable  to  speed  and  performance. 

Suppose  the  bow  to  be  straight,  as 
in  Fig.  3,  Plate  6,  from  each  section 
of  this  bow,  the  water  would  receive 
an  equal  velocity  ;  but  as  the  ship  is 
moving  ahead,  the  water  cannot  pass 
off,  particularly  if  she  is  moving  fast ; 
and  in  proportion  to  the  speed  there 
will  be  an  accumulation  at  7,  and  great- 
er at  6,  and  still  greater  at  1,  because 
the  accumulation  at  any  one  section 
prevents  the  outward  passage  of  the 
water  from  immediately  before  it, 
and  throughout  afterwards  ;    hence   it 


follows,  that  the  passage  of  the  water 
outward  from  the  first  section  will  be 
most  resisted,  and  an  accumulation 
will  take  place,  though  not  to  that  de- 
gree that  it  will  before  a  vessel  having 
a  convex  bow  ;  for  although  the  water 
at  No.  1  is  nearest  the  bow,  yet  it  must 
follow  that  of  all  the  sections  farther 
aft  whose  columns  are  equally  hard  to 
remove ;  hence  the  reason  why  the 
water  rises  higher  at  this  section  than 
on  any  other,  when  the  vessel  is  mov- 
ing fast  through  the  water  ;  and  it  will 
be  observed  that  the  bow,  like  No.  3, 
continues  to  impart  an  equal  velocity 
at  its  termination,  to  that  imparted  at 
the  commencement  of  the  bow. 

Having  given  the  objections  to  the 
convex  and  straight  bow,  we  will  pro- 
ceed to  describe  the  comparative  ad- 
vantages of  the  wave-bow ;  first,  by 
stating  the  object  desired  to  be  effected 
by  the  bow  of  the  ship,  which  is  to  dis- 
place the  water  sufficiently  to  admit  of 
the  passage  of  the  ship,  and  to  do  this 
with  the  least  possible  expenditure  of 
power.  It  has  been  seen,  that  if  the 
bow  be  convex,  as  in  Fig.  2,  Plate  6, 
the  motion  will  be  imparted  too  quick- 
ly, the  water  will  be  accumulated  at 
the  stern,  and  the  evils  already  shown 
will  arise;  or  if  it  be  formed  as  Fig.  3, 
the  motion  will  not  be  imparted  gradu- 
ally, and  therefore  a  rise  will  take  place 
close   forward,  only   in   a    less  degree. 


152 


MARINE   AND    NAVAL    ARCHITECTURE, 


Hence  it  follows,  that  the  form  which 
will  impart  the  velocity  gradually,  (for 
the  more  gradual  the  motion  the  less 
power  will  he  required  to  effect  it,)  and 
allow  it  to  subside  gradually,  must  be 
the  best.  It  will  to  seen  by  Fig.  4,  that 
the  velocity  imparted  by  each  section 
is  greater  than  that  imparted  by  the 
one  before  it  up  to  the  centre  of  the 
bow,  where  it  gradually  becomes  less 
and  less  to  the  termination  of  the  same; 
at  the  stem  there  Avill  be  no  accumu- 
lation, and  at  the  after-end  there  will 
be  no  deficiency,  and  that  form  will 
occasion  the  phenomena  called  a  wave  ; 
for  though  the  action  of  the  bow  is  to 
move  the  water  horizontally,  yet  as  its 
outward  motion  from  the  bow  of  the 
vessel  is  met  and  resisted  by  the  water 
farther  out,  it  can  only  escape  by  ri- 
sing above  the  surface  ;  and  of  course 
the  amount  of  rise  will  be  in  proportion 
to  the  outward  velocity  communicated. 
This  is  least  at  the  two  extremities  of 
the  bow,  and  most  at  the  centre  be- 
tween the  stem  and  its  after  termina- 
tion ;  therefore  the  result  will  be  a 
gradual  rise  from  the  stem  toward  the 
centre,  and  a  gradual  subsidence  from 
the  centre  toward  the  after  termina- 
tion of  the  bow,  or  in  other  words,  a 
icavc.  This  will  not  only  be  effected 
with  the  least  consumption  of  power, 
but  the  better  position  of  the  accumu- 
lation   will  have  marked    a    favorable 


influence  upon  most  of  the  properties 
of  the  ship. 

The  principles  wc  have  laid  down 
for  the  formation  of  vessels,  are  not 
entirely  new  in  the  old  world,  although 
quite  new  in  the  United  States.  Ri- 
valry has  given  an  impetus  to  improve- 
ments in  Europe  that  must  set  aside 
the  musty  folios  of  the  past  behind  the 
curtains  of  oblivious  drapery.  The 
British  Association  have  upset  the  old 
rules,  and  are  now  daring  not  only  to 
build  vessels  with  hollow  lines,  but  to 
place  the  greatest  transverse  section 
abaft  the  longitudinal  centre  of  the  ves- 
sel. The  following  proportions  which 
were  regarded  with  favor  both  in  Eng- 
land and  the  United  States,  are  now 
being  partially  reversed — the  placing 
the  greatest  transverse  section  two- 
fifths  of  the  length  from  the  bow,  is 
now  being  placed  aft  of  the  centre  of 
length.  As  a  precursor  to  those  im- 
provements, it  is  but  a  few  years  ago 
since  a  daring  adventurer  took  the  re- 
sponsibility of  breaking  the  law  of  pre- 
cedent, and  without  consulting  his  ri- 
vals in  the  art,  placed  the  dead-flat 
frame  at  the  longitudinal  centre  of  the 
vessel.  The  subsequent  action  of  the 
British  Association,  under  the  direction 
of  Mr.  J.  S.  Russell,  have  led  to  very 
important  results.  A  committee  was 
appointed,  whose  researches  and  in- 
quiries have  established,  by  a  series  of 


MARINE    AND    NAVAL    ARCHITECTURE. 


153 


experiments,  not  upon  the  smooth  sur- 
face of  a  mill-pond,  but  upon  the  ocean, 
a  set  of  very  curious  facts.  The  old- 
fashioned  principle  was,  that  the  water- 
lines  should  be  nearly  straight,  and  that 
there  should  never  be  a  hollow  line,  ex- 
cept a  little  in  the  run  of  the  ship,  but 
that  there  should  most  certainly  be  none 
forward — all  the  lines  on  the  bow  re- 
quiring to  be  convex — and  whenever 
any  bold  experimenter  would  refuse  to 
allow  public  opinion  to  think  for  him 
in  this  matter,  or  in  that  of  placing  the 
dead-flat  frame  farther  aft,  his  success 
was  set  down  as  an  exception,  and  not 
as  the  rule. 

Mr.  Russell  claims  for  himself  in 
Europe,  as  having  discovered  the  pro- 
per shape  for  the  water-lines,  which  he 
distinguishes  from  others  by  naming  it 
the  wave-principle.  Experiments  in 
the  United  States  have  fully  established 
the  practicability  of  placing  the  great- 
est transverse  section  as  far  aft  as  the 
longitudinal  centre  of  any  vessel.  It 
is  somewhat  surprising  that  the  same 
difficulties  in  determining  appropriate 
shapes  should  have  been  found  to  exist 
by  different  means.  While  adhering 
to  the  parallel,  or  to  the  inscribed  line 
of  flotation,  and  endeavoring  to  system- 
ize  the  principle  of  forming  vessels  from 
the  form  of  this  line,  as  shown  at  the 
surface,  in  England,  another  method 
was  adopted  in  the  United  States,  that 


will,  without  doubt,  prove  equally,  if 
not  more,  successful,  because  it  strikes 
at  the  root  of  the  matter.  While  the 
theories  of  the  old  world  only  skim  the 
surface,  the  experiments  in  this  coun- 
try have  been  based  upon  the  right- 
angled  pressure,  or  the  equilibrium  of 
fluids.  It  will  be  found,  that  by  obtain- 
ing the  shape  of  the  bow  of  a  ship  from 
the  model  at  right-angles  from  its  sur- 
face, we  shall  discover  that  this  line  is 
much  fuller  than  the  inscribed  line  of 
flotation  ;  and  that  to  reduce  its  full- 
ness to  that  of  straight,  or  nearly  so,  we 
make  the  line  of  flotation  hollow  ;  this 
may  be  seen  by  referring  to  the  dotted 
line  shown  in  the  half-breadth  plan  of 
Plate  2,  Sec.  1 :  it  will  be  discovered,  that 
although  the  load  water-line  is  straight, 
the  line  of  resistance  is  quite  round, 
but  not  sufficiently  round  to  generate 
a  wave  at  a  speed  of  seventeen  miles 
per  hour.  It  cannot  be  expected  that 
freighting-vessels  should  be  adapted  to 
high  speed,  but  they  may  be  built  to 
carry  all  they  now  do  in  a  much  short- 
er time. 

In  relation  to  the  wave-principle  we 
will  only  remark,  that  the  principle  is 
an  approximation  to  nature's  standard, 
but  the  manner  of  application  is  de- 
fective ;  the  motions  of  the  water 
around  the  vessel  are  deceptive  ;  the 
large  amount  of  hollow  aft  at  the  sur- 
face  is  wrong,  which  is  evident  from 


20 


154 


MARINE    AND    NAVAL    ARCHITECTURE, 


the  fact,  that  it  would  require  more 
rudder  to  steer  such  vessel  than  one 
having  less  hollow.  In  general  terms, 
we  may  also  add,  that  the  action  of  the 
fluid  around  the  bow  and  sides  of  the 
vessel,  would  perhaps  lead  the  casual 
observer  to  conclude,  that  the  revolu- 
tions were  horizontal  and  parallel  to 
the  surface  on  all  parts.  The  practice 
itself  would  have  a  tendency  to  mislead 
the  public  mind,  and  beget  and  nour- 
ish that  subtle  foe  to  all  improvement, 
prejudice,  which,  from  its  very  nature, 
is  contagions  ;  it  lurks  among  the  laby- 
rinths of  thought  ;  it  flashes  like  the 
electric  spark  with  every  glance  of  the 
eye  ;  it  may  be  seen  at  the  fountain  of 
knowledge,  mingling  its  insipid  proper- 
ties with  every  draught — this  bane  of 
all  progress  in  ship-building  has  been 
borne  down  in  the  ship-yard  by  the 
commingling  influence  of  interchange. 
The  young  operative  mechanic  finds, 
that  public  opinion  to  the  contrary, 
notwithstanding,  he  may  know  as  much 
about  putting  work  together  at  twenty- 
five  years  of  age,  (even  though  his 
father  might  not  have  been  a  ship- 
builder,) as  another  who  may  have  lived 
fifty  years,  and  whose  ancestors  were 
ship-builders  from  time  immemorial. 
The  desire  of  the  builders  to  make 
monev,  has  fostered  this  laudable  ainbi- 
tion,  and  hereditary  knowledge  has 
lost     much    of  its    attractive    charm 


in  practical  operations  in  the  United 
States.  Not  so,  however,  in  the  theory 
of  ship-building ;  this  insidious  foe  is 
feeding  on  the  very  vitals  of  scientific 
knowledge,  having  never  relinquished 
its  claim  to  the  hereditary  distinct  ions 
in  the  old  world,  from  whence  it  has 
been  transplanted  to  the  new,  and  its 
poison  distilled  and  diffused  as  widely 
as  our  commercial  interests  have  ex- 
tended. Few  minds  possess  that  ex- 
cretive power  necessary  to  throw  off 
the  cumbrous  mass,  and  not  only  as- 
sert, but  maintain  an  equilibrium  of 
thought  and  action. 

We  have  found  it  necessary  to  show 
in  a  former  chapter  some  of  the  bane- 
ful effects   of  drawing   hereditary   dis- 
tinctive lines  of  scientific  knowledge 
but  being  about  to  penetrate  these  il- 
lusive dreams  by  the  light  of  truth,  w< 
deemed  it  due  to  our  readers  to  sho> 
with  what  rapid  strides  this  herculean 
monarch  has  marched  over  the  whoh 
area  of  the  commercial  world.      Its  in- 
sidious   poison  has    been  diffused   not 
only  throughout  the  ship-yard,  in   it: 
every  department,  but  upon  the  ocean, 
in    the    counting-house,    and    at    tin 
domestic  hearth  around  the  fire-side 
thus  the  thinking  man  will  plainly  set 
that  the  milk  of  knowledge   lias   been 
curdled    at   the   fountain.      The    man 
who  professes  to  know  nothing  of  the 
peculiar  properties  of  models,  will  show 


MARINE  AND  NAVAL  ARCHITECTURE. 


1-55 


his  attachment  for  the  same  form  of 
water-line  as  his  friend,  and  with  an 
extension  of  knowledge  he  will  often 
endeavor  to  fortify  his  mind,  not  with 
arguments  in  their  defence,  but  witli 
the  prejudices  of  his  friends.  We  have 
known  many  whose  general  impres- 
sions would  have  been  correct,  provi- 
ded the  first  impressions  had  been  di- 
rected into  a  proper  channel ;  but  hav- 
ing taken  the  wrong  bias,  are  led  into 
the  prevailing  notions. 

It  is  not  against  prejudice  indiscrimi- 
nately that  we  wage  war ;  we  believe 
that  a  certain  amount  is  necessary,  and 
would  have  little  confidence  in  the  me- 
chanic's excelling  that  had  none  ;  but 
it  is  that  amount  that  prevents  the  ship- 
wright from  thinking  for  himself;  it  is 
the  man.  who  does  not  set  a  proper 
estimate  upon  his  own  thoughts,  and  is 
unable  to  shake  off  the  bias  that  other 
people's  opinions  have  made  upon  him, 
the  scales  of  whose  mind  are  not  pro- 
perly balanced,  having  a  weight  always 
in  one  side.  The  positions  laid  down 
are  not  the  deductions  of  theorists,  but 
the  result  of  tangible  demonstrations 
both  in  Europe  and  America.  Theory 
and  practice  agree  in  the  old  world, 
that  the  greatest  transverse  section 
should  be  farther  aft.  This  adjustment 
has  been  practised  by  the  Spaniards, 
recommended  in  France  by  scientific 
men,    and    approved    by   at  least    one 


builder  of  Portsmouth,  England,  having 
had  more  than  fifty  years'  experience  ; 
and  last,  though  not  least,  America,  as 
far  as  she  has  adopted  it,  has  had 
abundant  success,  as  we  shall  hereafter 
show. 

We  have  said  that  the  resistance 
met  by  the  moving  ship  was  not  in  the 
direction  of  the  inscribed  line  of  flota- 
tion ;  we  will  not  descend  below  the 
surface  until  we  have  endeavored  to 
show  this  above  water.  Has  not  the 
man  who  has  witnessed  the  action  of 
the  wave  against  the  bow  of  a  vessel 
noticed  that  it  was  thrown  off  at  right 
angles  ?  Does  not  our  every  day  expe- 
rience teach  us  this,  that  if  a  bow  has 
a  great  amount  of  flare,  the  water  falls 
proportionately  nearer  the  vessel  than 
from  a  bow  that  flares  less 7  Just  so 
with  the  stern  ;  from  the  ship  that  lias 
flat  buttocks,  the  water  will  fall  at  right 
angles  from  the  same;  the  shape  of 
the  bow  immediately  below  and  at  the 
surface,detcrminesthe  form  of  the  wave 
generated  ;  the  surface  is  the  starting 
point  for  every  particle  of  fluid  set  in 
motion  around  the  vessel ;  its  course  is 
determined  by  the  shape  of  the  im- 
mersed part  of  the  hull  ;  hence  il  is 
plain  that  the  direction  differs  materi- 
ally from  that  of  the  parallel  to  the  line 
of  flotation.  It  is  a  truth  known  to 
every  man  thai  water  moves  over  a 
perfect  plane  with  the  same   facility  in 


156 


MARINE    AND    NAVAL    ARCHITECTURE. 


one  direction  as  in  another,  while  the 
pressure  is  equal  ;  hence  it  is  quite 
apparent,  that  the  turning  of  the  mole- 
cules of  the  fluid  Avill  be  in  a  direction 
in  which  the  least  resistance  is  encoun- 
tered. We  may  suppose  a  vessel  to  be 
supported  entirely  by  musket-balls  of 
less  malleable  material  than  lead  ;  let  a 
cavity  be  formed  that  will  permit  a  ves- 
sel to  float ;  it  may  be  of  the  form  of  the 
greatest  transverse  section  ;  the  balls 
may  be  placed  under  the  vessel,  as- 
suming the  transverse  section  of  the 
cavity  to  be  exactly  the  size  of  the  balls 
larger  than  the  vessel ;  if  the  slip, 
box  or  dock  containing  the  vessel  were 
of  the  same  form  and  size  transversely 
at  each  end,  it  is  quite  plain  that  the 
vessel  would  rest  only  on  the  0  frame, 
which  is  quite  enough  for  our  purpose  ; 
the  vessel  may  now  be  grounded  on 
the  balls,  by  removing  or  letting  off 
the  water.  We  now  have  a  row  of 
balls  across  the  cavity  containing  the 
vessel,  under  the  keel  on  its  sides,  and 
from  the  garboard-seam  to  the  load- 
line  ;  the  vessel  may  now  be  moved 
forward,  and  let  our  readers  watch  in 
their  imagination  the  direction  of  the 
motion  of  the  balls — of  those  under  the 
keel,  the  axis  will  be  horizontal,  while 
those  on  the  sides  of  the  keel  will  have 
a  vertical  axis  ;  the  balls  under  the  bot- 
tom will  again  differ  from  those  sus- 
taining the  keel,  having  a  diagonal  axis. 


It  is  just  so  with  the  water  ;   and  this 
is  what  we  mean  when  we  say  the  di- 
tion  of  the  resistance  is  not  parallel  to 
the  lines  of  flotation,  but  at  right  angles 
with  the  adjacent  parts :  this  applies 
to  every  part  of  the  immersed  portion 
of  the  vessel.     These  remarks  are  de- 
signed principally  for  those  who  leave 
the  model,  and  suppose  they  can  make 
improvements  on  the  floor,  or  on  the 
draught.     It   requires  but  a  moment's 
reflection  to  satisfy  the  thinking-man, 
that  when  we  exchange  rotundity  in 
perspective,  for  delineations  by  section- 
al planes,  we  mistake  the  shadow   for 
the  substance.     It  is  impossible  to  mark 
any    discrepancy    in    form    only    from 
analogy  on  the  floor;  true,  by  distri- 
buting the  battens  on  both  bodies,  we 
prove  our  work,  but  to  determine  shape 
with  any  considerable   degree   of  cer- 
tainty, is  out  of  the  question.      Then 
is  scarce  a  builder  who  has  not  his  o\v 
peculiar  notions  in  relation  to  the  pro- 
per form  for  those  parallel  planes  ;  om 
decries  hollow  lines  on  both  ends  of  tin 
vessel ;   another    has   no  objection    t( 
the  hollow  on  one  end  ;  while  a  thin 
will  advocate  the  same  on  both   ends: 
thus  the  young  mechanic  is  led  to  sup- 
pose, that  by  following  his  employer.  <»i 
some    successful    builder,    he  has    dis- 
covered  the  universal   alcahest  for  all 
the    mysteries  beneath  the  surface  of 
the  fluid. 


MARINE    AND    NAVAL    ARCHITECTURE. 


157 


We  will  endeavor  to  analyze  the  re- 
sults of  this  assumption.  Were  the 
rotary  motion  of  the  particles  as  as- 
sumed by  the  adherence  to  the  parallel 
for  the  water-line,  we  would  find  that 
the  axis  of  every  molecule  operated  on 
by  the  moving  vessel,  would  be  vertical 
— a  consequence  that  even  the  casual 
observer  would  repudiate.  We  can  by 
no  stretch  of  the  imagination  admit  of 
such  direction.  It  at  once  destroys  the 
equilibrium  of  fluids,  and  annuls  every 
law  for  the  government  of  the  same. 
The  man  who  models  a  vessel  possess- 
ing those  views  in  relation  to  the  pa- 
rallel to  the  line  of  flotation,  cannot 
entertain  correct  views  of  the  first  im- 
pressions made  upon  the  fluid  by  the 
moving  vessel.  It  would  be  well  for 
him  to  make  his  model  by  lines  running 
as  near  at  right  angles  with  the  exterior 
surface  of  the  greatest  transverse  sec- 
tion as  may  be,  and  at  the  proper  dis- 
tance, for  determining  the  required 
shape. 

Assuming  that  enough  has  been  said 
in  this  chapter  upon  the  shape,  Ave 
shall  now  proceed  to  delineate  the  man- 
ner of  constructing  the  draught  with- 
out the  model.  It  has  been  the  prac- 
tice of  foreign  authors  to  furnish  the 
dimensions  of  different  ships,  and  at  the 
same  time  make  such  expositions  upon 
their  various  qualifications,  as  the  exi- 
gencies of  the  case  may  seem  to  de- 


mand. It  is  not  our  purpose  to  pur- 
sue a  similar  course.  Were  we  thus 
disposed,  we  should  doubtless  find  a 
bewildering  discrepancy  that  exists  in 
the  proportions  of  different  ships — 
which  would  leave  our  readers  still 
more  in  the  dark. 

We  have  already  given  proportions 
for  the  principal  dimensions  of  freight- 
ing-ships  in  the  United  States.  In  Eng- 
land the  depth  has  been  set  down  as 
being  proportionate,  when  it  equals 
from  five-ninths  to  two-thirds  of  the 
breadth — the  length  at  four  times  the 
breadth — but  for  speed,  Euler  found 
by  experiment,  that  six  feet  of  length 
for  one  of  breadth,  was  better  than  a 
less  proportion.  Exceptions  to  those 
rules  must  be  made,  according  to  cir- 
cumstances. 

Having  determined  the  principal  di- 
mensions, we  may  now  commence  the 
draught,  which  will  be  found  to  consist 
of  three  principal  plans,  called  the  sheer, 
the  half-breadth,  and  the  body-plan ; 
they  are  usually  drawn  in  as  many 
separate  places  on  the  paper,  which 
should  be  stretched  on  a  board  pre- 
pared for  the  purpose.  Although  the 
draught  consists  of  three  plans,  but  two 
only  are  necessary  to  determine  the 
form  of  the  ship;  the  third  may  be  de- 
duced from  the  other  two. 

The  usual  arrangement,  and  the  one 
With  which  the  eye  has  become  familiar, 


168 


MARINE    AND   NAVAL    ARCHITECTURE. 


is  that  of  drawing  the  sheer-plan  on 
the  upper  i>;irt  of  the  sheet,  while,  im- 
mediately below,  the  half-breadth  plan 
is  drawn,  and  the  body-plan  is  drawn 
either  ahead  or  astern,  when  the  paper 
is  sufficiently  large  ;  but  when  this  is 
not  the  ease,  it  is  sometimes  projected 
on  the  middle  of  the  sheer-plan.  Be- 
ginning with  the  profile  or  sheer-plan 
above,  we  must  leave  ample  room  be- 
low for  the  half-breadth  plan,  which 
an  ill  require  more  spaee  than  the  actual 
halt-width  of  the  ship.  We  shall  find 
ii  convenient  to  first  secure  the  paper 
on  the  board  by  gluing  the  edges  down  ; 
after  having  wet  the  wrong  side  of  the 
paper,  one  quarter  of  an  inch  of  gluing 
surface  around  the  edge  of  the  paper, 
is  sufficient  ;  it  should  be  partially  dried 
with  a  warm  iron,  in  order  that  it  may 
be  perfectly  so  before  the  paper  shrinks 
much,  as  the  contracting  power  is  very 
great,  and  would  tear  up  the  vx\grs 
unless  the  glue  was  quite  dry.  The 
right  side  of  drawing-paper  is  the 
smooth  side,  or  the  side  from  which 
the  maker's  name  can  be  read  from 
left  to  right.  The  edge  of  the  board 
should  be  straight,  and  at  right  angles 
with  the  ends ;  we  shall  find  this  to  be 
quite  essential  in  working  with  the  T 
square  ;  the  use  of  which  materially 
facilitates  the  work  in  marking  straight 
parallel  lines  to  the  base  of  the  board, 
or  lines  al    right  angles   with  the  base. 


Begin  with  the  sheer-plan,  showing  a 
broad  side  view  ofthc  ship, and  in  which 
the  lengths  and  heights  of  all  the  lines 
are  shown.  The  perpendiculars  may 
be  erected  upon  the  base-line,  and 
should  extend  from  the  margin-line  for- 
ward at  the  stem,  and  on  the  load-line 
of  flotation  to  the  margin-line  on  the 
post,  at  the  same  altitude  ;  the  base- 
line represents  the  upper  edge  of  the 
keel,  as  has  been  fully  shown  in  the 
last  chapter.  From  the  base  we  may 
square  up  a  line  representing  the  dead- 
flat  frame,  determining  first  upon  its 
proper  location;  this  we  recommend 
to  be  about  the  centre  of  the  space 
between  the  perpendiculars  in  freight- 
ing or  sailing  ships,  for  the  obvious  rea- 
son that  the  custom  has  prevailed  al- 
most universally  of  trimming  ships  by 
the  stern,  which  brings  the  dead-flat 
frame  of  the  ship  (having  a  long  fore 
and  aft  floor)  farther  aft  on  the  bottom 
than  the  builder  designed  that  it  should 
be  ;  hence  it  must  be  quite  apparent) 
that  if  the  dead-flat  frame  were  placed 
farther  aft,  and  the  ship  trimmed  near- 
ly upon  an  even  keel,  the  frame  would 
nominally  be  in  the  same  place.  Upon 
this  point  (in  this  place)  it  may  only  be 
necessary  to  say,  that  inasmuch  as  it  is 
almost  universally  admitted  that  the 
centre  of  gravity  of  the  ship  should  be 
near  the  longitudinal  centre — an  admis- 
sion which  puts  a  quietus  on  every  argu- 


MARINE   AND    NAVAL    ARCHITECTURE. 


159 


ment  against. having  the  greatest  trans- 
verse section   in  the   same  place — we 
may  now  prepare  the  halt-breadth  plan, 
by  drawing  a  line  parallel  to  the  top  of 
the  keel,  and  at  the  same  time  parallel 
to  the  edge  of  the  board;  run  down  the 
perpendiculars  to  this  new  line,  which 
is  the  middle-line,  showing  the  longitu- 
dinal and  transverse  centre  of  the  ship  ; 
these  lines,  as  all  subsequent  ones,  until 
our    readers    are    notified,    should    be 
marked  with  pencil  only  ;   the  dead-flat 
may    also   be    continued  down   to  the 
middle-line.     Our  next  course  should  be 
to  prepare   a   body-plan,  which   is   de- 
signed to  show  the  moulding  shape,  or 
edge  of  all  the  frames,  this  plan  is  made 
to  conform  with  the  breadth  and  depth 
of  the  ship  at  the  dead-flat  frame,  from 
the  base-line  or  top  of  the  keel,  to  the 
lower  side  of  the  rail.     After  having  its 
boundary  line,  we  may  mark  in  the  <3> 
frame,  assuming  that  it  represents  the 
lowest  part  of  the  bottom  from  the  base- 
line outward ;   also  assuming  it  to  be 
the  widest  frame  in  the  ship,  it  is  not 
uncommon  to  have  several  frames  by 
the  same  moulds  ;  this,  however,  is  no 
advantage,  even  though  the  ship  may 
be    designed    for    burden    only ;    from 
this  frame  we  may  determine  the  loca- 
tion of  the  several  sheer  and  deck-lines, 
by  setting  up  their  heights  above  base, 
remembering    that    the    line    showing 
the  top  height  or  the  lower  side  of  the 


plank-sheer,  is  above  the  deck-line,  the 
depth  of  the  water-way,  which  varies 
from  twelve  to  fifteen  inches.  The 
depth  of  hold  is  taken  from  the  top 
of  the  beam  in  the  main  hatch  to  the 
top  of  the  ceiling  alongside  of  the  keel- 
son ;  from  this  we  may  be  able  to  de- 
termine the  required  depth  of  the  dead- 
flat  frame,  and  the  proper  location  for 
the  load-line,  for  which  see  page  43. 
Should  we  determine  to  have  a  projec- 
tion at  the  top  of  the  wale,  we  should 
at  once  fix  upon  the  width  of  the  strings, 
or  those  narrow  strakes  immediately 
below  the  plank-sheer,  and  above  the 
wale;  thus  we  are  furnished  with  those 
sheer-lines — the  wale,  or  first  height, 
the  lower  side  of  the  plank-sheer,  or 
second  height,  and  the  lower  side  of 
the  rail,  or  third  height.  It  will  be  re- 
membered, that  when  the  distance  of 
those  lines  from  the  base,  or  from  load- 
line  is  measured,  they  are  heights;  but 
when  measured  to  the  middle-line,  or 
horizontally,  they  are  breadths.  We 
make  this  remark,  lest  we  may  not  be 
distinctly  understood,  as  this  mode  of 
mtVning  sheer-lines  is  perhaps  not  gen- 
erally known  even  in  the  private  yards. 
In  Europe,  the  lower  or  first  sheer-line 
is  called  the  height  of  breadth,  top- 
height,  and  rail-breadth,  but  the  course 
we  have  adopted  is  readily  understood. 
We  may  now  set  up  those  heights  on 
the   dead-flat    frame  in  the  sheer-plan. 


160 


MUUNE    AND    NAVAL    ARCHITECTURE. 


and  having  first  swept  in  the  margin- 
line,  or  inside  of  the  stem,  cutting  the 
perpendicular  at  load-line,  and  in  its 
continuance  intersecting  the  base  as  far 
aft  as  the  forward  square-frame,  (for 
reasons  shown  on  page  118,)  thence  to 
the  stern-post,  the  inside  of  which  also 
cuts  the  rabbet  at  the  load-line,  and  from 
a  point  near  its  head,  projecting  the 
counter  and  stern,  or  the  line  repre- 
senting the  centre  of  the  same.  We 
may  here  remark  that  the  point  from 
which  the  counter  projects  from 
the  post,  is  called  the  cross- seam, 
from  the  division  which  here  takes 
place  between  the  bottom-plank  which 
end  here,  and  the  plank  above  which 
seam  here,  and  end  on  the  quarters. 
This  division,  however,  applies  to  the 
sterns  of  ships  as  they  have  been  built ; 
but  we  cannot  suppose  that  the  prac- 
tice will  be  long  continued  when  its  de- 
fects become  generally  known.  This 
line  of  division  referred  to  is,  and  must 
necessarily  continue  to  be,  the  weakest 
part  of  the  stern.  It  requires  but  a 
glance  to  discover  that  this  is  not  only 
a  division  in  the  plank,  but  that  it  ex- 
tends to  the  timbers  which  are  dove- 
tailed into  the  transom ;  and  it  must 
be  also  apparent,  that  it  is  either  ne- 
cessary that  the  plank  from  the  bottom 
should  extend  as  high  as  the  upper  edge 
of  the  counter,  thus  covering  the  weak- 
er part,  or  that  the  stern-frame  should 


become  obsolete  we  may  adopt  either; 
the  cross-seam  may  for  the  present  be 
located  in  its  usual  place  :  its  height 
must  be  determined  to  some  extent  by 
circumstances  ;  but  the  higher  we 
are  able  to  get  it,  the  better  shape  we 
may  obtain.  The  difficulties  in  loca- 
ting the  ordinary  cross-seam  high  are, 
first,  we  are  deprived  of  light  between 
decks,  by  crowding  up  the  cabin  win- 
dows ;  this  brings  them  in  range  of  the 
deck-beams.  Custom  has  made  it  a  law 
(and  we  know  of  no  other)  that  there 
must  be  counter  enough  to  cover  the 
rudder,  and  something  to  spare  ;  it  has 
also  determined  that  there  must  be  an 
arch-board,  and  that  the  cabin  win- 
dows must  come  above  the  arch-board. 
The  second  objection  (which  is  not  an 
objection  in  reality)  is,  that  the  wale 
must  twist  under  at  the  after-end  if  the 
cross-seam  is  high,  as  in  Plate  5.  With 
these  remarks  we  leave  the  subject, 
allowing  our  readers  to  place  it  where 
they  please. 

We  may  now  hang  the  sheer-lines 
at  the  several  heights  on  the  dead-flat 
frame,  and  ending  for  the  present  on 
the  stern,  and  on  the  margin-line  for- 
ward, which  should  be  continued  as 
high  as  the  rail  is  designed  to  be.  Our 
remarks  upon  sheering  in  the  last  chap- 
ter will  apply  here  equally  well;  we 
will  only  add,  that  the  amount  of  sheer 
is  a  matter  of  taste  ;   one  quarter  of  an 


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MARINE    AND    NAVAL    ARCHITECTURE. 


161 


inch  to  the  foot  at  the  wale,  and  one- 
eighth  at  the  rail  for  a  large  ship,  can 
he  distributed  to  look  well.  Assuming 
that  the  sheer-lines  have  been  disposed 
of,  we  may  now  divide  that  part  of 
the  sheer-plan  into  parallel  and  equal 
spaces  between  the  base  and  load-line  ; 
the  lower  space  should  be  less  than 
those  above,  becaase  of  the  advantage 
obtained  in  having  a  line  near  the  base 
of  the  bilge,  or  its  lower  part ;  these 
lines  extend  from  the  margin-line  for- 
ward to  the  same  on  the  post,  and  may 
be  marked  in  with  ink  ;  they  are  usu- 
ally called  water-lines ;  the  base-line 
may  also  be  marked  in  with  ink ;  also 
the  stern,  counter,  margin  of  post,  and 
stem,  as  high  as  the  bow-sprit.  It  may 
be  well  to  add,  that  the  ink  used  for 
mechanical  drawings  is  India  ink,  and 
should  be  mixed  by  being  rubbed  on  the 
finger  after  dipping  one  end  in  clear 
soft  water ;  but  a  few  drops  only  are 
necessary  to  mix  at  one  time,  and  should 
be  kept  entirely  free  from  dust.  One 
of  the  great  secrets  in  drawing  a  hand- 
some draught  with  even  or  smooth  lines, 
will  be  found  in  that  of  having  the  ink 
pure,  and  cleaning  out  the  pen  before 
laying  it  down  ;  the  insides  of  the  pen 
must  be  entirely  free  from  any  con- 
gealed ink,  or  it  will  not  work  to  the 
satisfaction  of  a  man  of  taste. 

We   now   have  all    the  longitudinal 
lines  we  require  at  present,  and  may 


next  divide  the  length  into  vertical 
spaces,  after  determining  the  timbering- 
room  we  require,  or  the  distance  we 
resolve  to  have  the  frames  apart  ;  the 
fourth  frames  may  now  be  set  off  on 
the  base-line  each  side  of  the  dead-flat 
frame — this  arrangement  may  extend 
the  entire  length  of  the  sheer-plan,  but 
may  not  be  marked  with  ink  beyond 
the  forward  and  after  square-frame  ; 
these  square-frames  are  so  called,  be- 
cause they  not  only  stand  square  across 
the  ship,  but  have  a  floor-timber  at- 
tached to  them  across  the  keel;  as  floors 
cannot  be  connected  with  cant  frames, 
they  are  carried  no  farther  than  the 
square- frames  extend.  The  practice 
of  canting  frames  from  a  transverse 
line  across  the  keel,  is  found  to  econo- 
mize timber  very  much,  this  being  the 
principal  reason  why  it  was  adopted  in 
this  country  some  fifty  years  ago  ;  the 
round  of  the  bow  and  buttocks  in- 
creases the  bevel  of  the  timbers,  and  as 
a  consequence,  renders  it  necessary  to 
have  larger  timber  to  make  the  same 
futtock  than  the  cant  frame  would 
require  ;  the  frame  being  canted,  the 
futtock  may  be  made  of  a  smaller  sized 
piece.  But  this  is  not  all;  the  fastening 
is  distributed  to  much  better  advantage 
on  cant,  than  on  square-frames,  even 
of  a  tolerably  sharp  vessel.  There  are 
exceptions  however  to  this,  found  on 
the  bow  of  a  very  sharp  steamer  or 


21 


162 


MARINE    AND    NAVAL    ARCHITECTURE. 


steamboat.  About  the  usual  propor- 
tionate space  allotted  for  cants  may  be 
seen  in  Plate  3  or  Plate  7.  No  deter- 
minate space  however  for  the  cants 
can  possibly  apply  to  all  vessels — the 
shape  of  the  vessel  must  furnish  the 
builder  with  all  that  his  judgment  may 
require — after  having  set  off  the  fourth 
frames  parallel  to  the  dead-flat,  which 
should  be  exactly  square  from  the  base, 
or  perpendicular  to  that  line  ;  and 
not  only  this  frame,  but  all  the  lines 
representing  frames  in  the  sheer-plan, 
should  be  at  right  angles  with  the  base 
and  middle-lines.  One  of  the  simplest 
modes  of  raising  a  perpendicular  may 
be  seen  in  Plate  7,  and  may  be  thus  de- 
scribed— a  base  of  six  feet,  perpendicu- 
lar of  eight  feet,  and  a  hypotenuse  of 
ten  feet,  all  measured  by  the  scale  upon 
which  the  draught  is  drawn,  or  all  by 
the  same  scale  :  the  frames  should  now 
be  named  as  described  on  pages  121 
and  122,  and  the  heights  taken  on 
every  fourth  frame  above  the  load-line, 
then  transferred  to  the  body-plan,  as 
shown  on  Plate  7,  and  described  on 
page  130.  It  will  be  remembered,  that 
we  have  the  full  dead-flat  frame  swept 
in  on  both  sides  ;  one  side  of  this  plan 
belongs  to  each  body:  it  is  usual  to 
place  the  fore-body  on  the  right,  as  in 
Plate  7 — this  indicating  the  draught 
to  he  what  is  called  a  starboard  or 
right-handed  draught.     We  only  name 


this  because  the  great  mass  of  iiie- 
chanics  are  unwilling  to  step  aside  from 
the  beaten-track,  even  though  nothing 
could  possibly  be  lost  by  it.  It  makes 
no  difference  which  side  of  the  body- 
plan  the  fore  or  after-body  may  be 
placed;  if,  however,  the  stem  is  to  the 
right  in  the  sheer-plan,  it  shows  the 
starboard  side  of  the  ship,  so  also  the 
fore-body  on  the  right  of  the  body-plan 
shows  the  starboard  side  :  it  is  the 
same  aft.  We  may  now  take  off  the 
half-breadth  of  the  load-line  on  the 
dead-flat  frame  from  the  body-plan,  and 
set  off  the  same  in  the  half-breadth 
plan — likewise  the  half-breadth  of 
the  several  sheer-lines  at  their  cor- 
responding heights  in  the  body-plan 
may  also  be  transferred  to  the  half- 
breadth  plan  ;  this  should  not  be 
done  with  the  dividers,  but  with  a  nar- 
row slip  of  paper,  as  all  other  trans- 
ferred measurements  should  be  taken. 
The  dividers  are  useful  in  their  place, 
but  their  points  should  not  be  inserted 
into  the  draught — the  beauty  of  a 
draught  is  gone  when  it  is  riddled  with 
holes,  which  may  be  easily  avoided,  and 
no  time  lost  by  using  the  slip  of  paper 
in  their  stead. 

The  side-line  next  demands  a  share 
of  our  attention.  This  line  represents 
the  side  of  the  keel, stem,  and  stern-post, 
and  should  extend  in  the  half-breadth 
plan  from  the  head  of  the  stem  as  far 


MARINE    AND    NAVAL    ARCHITECTURE 


163 


aft  as  its  intersection  with  the  base- 
line— (we  mean  by  the  head  of  the  stem) 
— in  perpendicular  line  with  its  head, 
and  in  the  same  manner  with  regard  to 
its  intersection  with  the  base  ;  likewise 
aft,  the  side-line  should  extend  from 
the  head  of  the  post,  or  from  cross-seam 
to  the  base-line,  that  is  to  say — if  the 
post  has  three  feet  of  rake  from  a  per- 
pendicular line,  the  length  of  the  side- 
line should  also  extend  three  feet.  See 
page  126  and  Plate  4.  The  side-lines 
must  only  be  marked  in  pencil  line.  We 
may  now  square  down  the  intersections 
of  the  water  and  sheer-lines  with  the 
margin-line  from  the  sheer-plan  to  the 
half-breadth  plan,  marking  a  spot  on 
the  side-line  for  each  water  and  sheer- 
line,  both  forward  and  aft.  We  may 
now  determine  the  form  of  the  load- 
line,  having-  its  breadth  on  the  dead- 
flat  determined,  and  its  ending-  partially 
so,  and  may  spread  out  half  of  the 
moulding-size  of  the  ship  on  this  line. 
We  have  already  shown  that  this  line 
is  the  inscribed  line  of  flotation,  and  its 
shape,  or  rather  a  shape  that  will  suit 
us,  is  doubtless  determined  sooner  or 
more  readily  at  this  part  of  the  ship, 
than  at  any  other.  At  the  first  sight 
of  a  ship  afloat,  (when  near  enough,)  the 
eye  seems  involuntarily  to  run  along-  the 
water-line,  and  our  mind  is  often  soon 
made  up  with  regard  to  the  form  below 
water.      We   are   speaking   in    general 


terms  to  show  why  we  have  began  here 
to  form  the  half-breadth  plan,  and  we 
will  farther  add,  that  to  those  who  have 
familiarized  the  eye  to  the  water,  or 
parallel  to  the  line  of  flotation,  this 
will  doubtless  be  the  readiest  mode  of 
obtaining  a  form  that  will  please  them 
in  its  rotundity.  What  we  have;  al- 
ready said,  and  may  hereafter  say  with 
regard  to  shape,  will  doubtless  be  all 
sufficient.  We  have  undertaken  in 
these  expositions  on  drawing  a  draught 
to  show  the  manner,  and  not  the  mat- 
ter, and  further,  that  we  may  more 
certainly  make  subjects  plain  that  have 
not  been,  we  are  persuaded,  that  by 
having  the  model,  the  floor  of  the 
loft,  and  the  draught,  we  shall  be  able 
to  accomplish  our  object.  Hence  it 
will  not  be  expected  that  improvements 
will  be  introduced  in  the  draught  when 
formed  by  the  eye  alone — this  is  not 
the  field  for  improvement  ;  neither  are 
we  willing  to  encumber  the  pages  of 
this  work  with  a  description  of  the 
many  futile  efforts  at  designing  the 
bodies  of  ships  by  mechanical  methods, 
which  have  in  former  times  been  sub- 
stituted for  correct  principles :  these 
methods  may  be  found  in  the  musty 
folios  of  the  past,  where4  it  is  best  that 
they  should  remain. 

Such  methods  of  endeavoring  to 
compensate  for  the  absence  of  more 
correct  principles,  on  which   to  found 


J  64 


MARINE    AND   NAVAL    ARCHITECTURE. 


the  design  of  a  ship,  were  supposed  to 
be  rendered  necessary,  whenever  the 
vessel  to  be  built  was  of  too  large  a 
size  to  admit  of  being  conveniently  put 
up  by  the  aid  of  the  eye  alone ;  and 
consequently,  almost  every  merchant- 
builder  of  the  old  world  is  in  posses- 
sion of  some  such  empirical  system, 
to  enable  him  to  form  a  design  for  a 
ship  ;  whether  the  ship  built  after  the 
design  so  formed  possessed  good  or  bad 
qualities,  did  not  generally  enter  into 
the  consideration  farther  thanthe  crude 
ideas  of  the  projector  may  have  guided 
him  in  forming  it.  We  say  crude  ideas, 
because  the  builder  whose  judgment  is 
sound  enough  to  enable  him  to  arrange 
facts  and  classify  observations,  whose 
experience  has  been  of  sufficient  ex- 
tent to  have  furnished  him  with  an 
array  of  truths,  from  which  to  deduce 
principles,  will  abandon  all  such  at- 
tempts as  futile,  and  will  pursue  the 
study  of  the  art  in  the  manner  in  which 
it  can  alone  be  studied  to  certain  ad- 
vantage, that  is  as  an  inductive  science, 
and  his  success  will  depend  on  his  fit- 
ness for  the  task.  The  mechanical 
methods  alluded  to,  may  be  found  in 
different  English  and  French  works 
on  Naval  Architecture — Steel,  Mur- 
ray, Bouguer,  La  Pere,  Fournier,  M. 
de  Pahni,  and  others,  some  of  which 
have  been  copied  by  Inter  authors. 
We    have   examined  the    parabolic 


system  introduced  by  Chapman,  and 
cannot  suppose  that  its  distinguished 
inventor  designed  its  introduction  to 
supplant  the  more  rigorous  application 
of  philosophical  principles,  as  some 
modern  authors  would  seem  to  infer. 
We  have  been  led  to  this  conclusion 
from  the  fact  that  its  principles  arc 
based  on  analogy  or  comparison,  de- 
termining nothing  tangible  in  relation 
to  its  adaptation  to  laws  governing  the 
element  the  vessel  is  designed  to  navi- 
gate, and  that  to  enable  the  practition- 
er to  make  use  of  this  method,  he  must 
acquire  a  knowledge  of  the  higher 
branches  of  mathematics,  to  calculate 
the  exponents,  as  it  is  a  system  of  ex- 
ponential formulas,  determined  from 
the  areas,  first  of  transverse  and  next 
of  longitudinal  sections. 

It  must  appear  obvious  to  the  think- 
ing-man, that  any  method  having  for  a 
basis  the  determination  of  the  form  of 
the  transverse  sections  from  sectional 
areas,  and  from  which  to  base  the  form 
of  the  longitudinal  sections,  must  be 
indeed  crude.  What  has  the  peculiar 
shape  of  any  form  in  a  ship  to  do  with 
determining  anything  more  than  the 
stability,  or  to  prevent  her  from  rolling? 
But  the  parabolic  system  does  not  even 
determine  this  point ;  and  it  may  be 
safely  said  that  no  system  is  worthy  of 
consideration  that  has  for  a  basis  sec- 
tional lines    at   right   angles   with    the 


MARINE   AND    NAVAL    ARCHITECTURE. 


165 


course  of  the  vessel  when  performing 
her  evolutions  upon  the  trackless  dee}), 
as  we  will  show  in  the  following  chapter. 
We  have  given  some  of  our  reasons 
for  determining  what  shape  we  require 
from  the  half-breadth  plan,  and*  may 
also  add,  that  no  man  who  takes  his 
eye  for  an  index  to  shape  in  its  rotun- 
dity, can  possibly  tell  either  in  convey- 
able  expositions  to  others,  or  portray  to 
his  own  mind  what  form  his  vessel  will 
be  from  the  transverse  sections.  It 
was  for  the  purpose  of  showing  what 
the  half-breadth  plan  really  is,  that  we 
have  departed  from  the  course  pursued 
by  our  predecessors,  who  have  inva- 
riably began  with  their  expositions  on 
the  body-plan,  and  drawn  all  their  de- 
ductions from  the  same.  We,  however, 
have  only  shown  the  greatest  transverse 
section  as  a  boundary-line  for  regula- 
ting practical  stability  and  determining 
heights  at  the  several  sheer-lines  ;  from 
this  frame  we  find  a  boundary-line  for 
the  extreme  breadth  of  all  the  lines  in 
the  half-breadth  plan  ;  and  having  the 
load-line  swept  in  with  pencil,  we  may 
proceed  to  form  the  rail  at  its  lower 
side,  having  already  the  settings-off  for 
the  midship-frame  and  the  ends :  one 
or  two  other  water-lines  may  also  be 
penciled  in  the  same  manner.  There 
was  a  time  when  this  was  a  tedious 
process,  inasmuch  as  it  required  a 
mould  for  every  line,  made  of  some  very 


thin,  close-grained  wood  ;  but  lines  on 
any  part  of  the  draught  may  now  be 
readily  swept  in  by  the  use  of  weights 
and  battens,  which  are  held  to  any  re- 
quired form  by  the  point  of  a  wire  in- 
serted into  the  end  of  the  weight,  and 
bent  down  to  the  lower  surface  of  the 
same,  within  the  thickness  of  drawing- 
paper  of  its  base.  This  precaution  is 
necessary,  for  in  case  the  weight  should 
slip  off  the  batten,  the  paper  would 
receive  no  damage  from  the  point,  it 
being  too  short  to  reach  the  paper. 
The  battens  may  be  made  of  steel, 
cedar,  or  ebony — the  latter  is  best — 
holly  is  good  for  battens.  The  weights 
may  be  of  lead  or  cast  iron,  with  a  hole 
cast  in  the  heaviest  end,  into  which  a 
plug  of  wood  may  be  inserted,  and  af- 
terwards a  wire  driven  into  the  plug, 
then  the  end  brought  to  a  point,  and 
bent  down  the  required  distance  ;  one 
dozen  weights  are  enough  to  draw  the 
draught  of  any  sized  vessel.  We  have 
found  those  we  use  to  be  second  to 
none  that  we  have  seen ;  they  weigh 
3\  pounds,  measure  7  inches  in  length, 
are  l{  inches  of  parallel  width,  by  2 
inches  deep  ;  the  hinder  end  is  thin, 
while  the  bulk  of  weight  is  brought 
near  the  end  into  which  the  wire  is  in- 
serted. The  sides  of  the  forward  end 
may  be  rounded  off,  that  two  points 
may  be  brought  near  together.  The 
shape  is  a  matter  of  taste  to  some  ex- 


1G6 


MARINE    AND    NAVAL    ARCHITECTURE. 


tent.  The  hole  should  he  oblong-,  and 
be  cast  in  the  weight,  inasmuch  as  the 
shape  and  roughness  of  the  hole  will 
hold  the  plug  firmly,  which  a  drilled 
hole  cannot  do.  Having  temporarily 
swept  in  one  or  two  lines  below  the 
load-line,  we  may  take  off"  every  fourth 
frame  midship,  as  before  directed,  upon 
a  slip  of  paper,  beginning  on  either  side 
of  the  dead-flat  frame,  and  continuing 
to  the  bow  or  stern,  near  which  we 
may  omit  hut  one,  taking  every  second 
frame  :  the  half-breadth  being  taken 
from  the  middle-line  on  the  frame  to  be 
shown  in  the  body-plan  to  the  inscribed 
line,  represented  both  in  the  sheer  and 
body-plan.  Having  thus  taken  off  all 
the  half-breadths  of  any  one  line,  we 
may  transfer  them  to  the  body-plan, 
and  after  performing  the  same  evolu- 
tions with  the  load-line  and  rail,  we 
may  bend  the  batten  to  the  spots,  pro- 
vided a  fair  frame  may  be  obtained  by 
following  the  spots ;  if  either  of  the 
lines  below  the  load-line  should  be  found 
to  vary,  we  may  note  the  discrepancy, 
and  try  another  frame  ;  should  the  same 
error  be  discovered,  we  may  transfer 
the  variation  to  the  half-breadth,  and 
again  place  the  batten  to  the  spots  thus 
altered.  Those  frames  when  found  to 
compare  in  both  bodies,  may  be  mark- 
ed in  with  pencil — the  line  showing  the 
form  of  the  vessel  at  the  wale,  or  the 
line    called    first-breadth,  may   now   be 


taken  off  from  the  frames  on  the  body- 
plan, and  transferred  tothe  half-breadth, 
the  after-end  running  out  fair,  aft  of 
the  last  frame  taken  oft".  The  lower 
side  of  plank-sheer  or  second-breadth, 
may  also  be  transferred  to  the  half- 
breadth  in  the  same  manner,  the  after- 
end  running  out  fair  aft  of  the  last 
frame.  Should  there  be  a  discrepancy, 
it  may  be  regulated  by  altering  the 
frames  so  as  to  correspond,  by  being 
fair  on  both  bodies.  When  the  sheer- 
lines,  or  breadths,  load-line,  and  two  or 
more  water-lines,  are  formed  both  to 
correspond  with  what  we  have  deter- 
mined to  be  the  proper  form,  we  may 
venture  to  run  in  the  remaining  water- 
lines,  and  regulate  the  fourth  and  in- 
termediate frames  to  correspond  wit  I 
the  same.  Should  we  require  a  givei 
amount  of  displacement,  it  will  be  ne- 
cessary to  determine  what  amount  the 
present  shape  will  furnish  before  we 
proceed  farther.  It  will  be  remember- 
ed, that  the  calculation  need  extend  no 
higher  than  the  load-line ;  and  if.  after 
the  calculations  have  been  made,  we 
fall  short,  or  overrun  the  required  dis- 
placement, we  must  make  such  altera- 
tions in  the  form  as  will  furnish  the 
required  amount.  It  will  be  seen  that 
neither  of  the  modes  shown  in  the  first 
chapter  will  apply  to  the  draught — thei 
are  designed  for  the  model  only. 
I  Hence  it  is  plain,  that  we  must  obtaii 


MARINE    AND    NAVAL    ARCHITECTURE 


167 


the  areas  of  all  the  water-lines,  if  we 
would  determine  the  exact  amount  of 
water  displaced  ;  but  this  is  seldom 
necessary,  unless  the  vessel  to  be  built 
be  a  steamer,  or  a  river-boat  of  very 
light  draught  of  water  ;  for  all  ordinary 
purposes,  it  is  quite  sufficient  to  deter- 
mine the  area  of  say  five  of  the  frames 
from  the  body-plan,  between  the  base 
and  load-line,  one  of  which  should  be 
the  dead-flat  frame  ;  add  the  five  areas 
together,  and  divide  by  five,  which  will 
give  the  mean  area  of  the  whole.  The 
manner  of  determining  the  location  of 
such  frames  as  should  be  selected,  may 
be  as  follows  :  divide  both  the  fore  and 
after-body  between  the  dead-flat  frame 
and  the  perpendiculars  into  three  equal 
parts — this  of  course  makes  four  set- 
tings-off", one  of  which  is  the  dead-flat, 
and  another  the  stem  or  post — the  other 
two  those  required ;  mark  in  the  sheer 
and    half-breadth    plans    a    temporary 


frame  at  those  two  settings-off  each  side 
of  the  dead-flat.  If  the  settings-off 
should  not  come  on  a  frame,  or  assu- 
ming that  they  come  between  the  frames 
already  swept  in,  then,  after  marking 
the  two  frames  at  the  settings-off  in 
each  body,  we  may  proceed  to  take 
them  off  the  half-breadth,  and  transfer 
them  to  the  body-plan,  from  which  the 
areas  may  be  taken  ;  after  which,  the 
formula  may  be  thus — let  L  be  the 
length  between  the  perpendiculars  ;  A 
1  the  area  of  the  forward  section  ;  A  2 
of  the  second  section  ;  A  3  that  of  ®  ; 
A  4  that  of  the  next  section  aft  of  dead- 
flat ;  and  A  5  the  after  section.  Then 
let  A  1  =  218  square  feet;  A  2=4S2 
square  feet  ;  A  3=532  square  feet  ; 
A  4=480  square  feet;  A  5=220 
square  feet;  and  H=15  feet,  the  dis- 
tance between  base  and  load-line;  L  = 
175,  the  length  between  the  perpen- 
diculars;  add  the  areas  together  thus: 


Al=21S+A2=4S2+A3=532+A4==4S0+A5=227=1931-r5:=3SGxl75=G7550-35==1930  tons. 


To  which  we  may  add  one-eighteenth 
of  the  same  for  the  plank,  keel,  stem 
and  post.  This  is  no  doubt  as  near  as 
we  can  arrive  to  the  exact  displace- 
ment from  the  draught,  without  enter- 
ing into  the  entire  calculation.  It  is 
true,  that  if  we  were  to  divide  the 
length  into  a  greater  number  of  parts, 
and  take  the  mean  of  a  larger  number 
of  sections,  we  should  arrive  nearer  the 


exact  displacement,  but  this  will  enable 
us  to  determine  whether  we  have 
enough  displacement  ;  and  if  we  have 
too  much  or  too  little  we  can  contract 
or  expand,  as  our  circumstances  may 
require,  but  we  will  follow  this  formula 
into  another  shape,  and  reduce  this  to 
capacity  ;   let  the  plank  be  added — 


1930  +  X  =  3037  tons. 


168 


MARINE    AND    NAVAL    ARCHITECTURE. 


From  this  four-ninths  must  be  deduct- 
ed for  the  weight  of  the  ship  ;  we  then 
have 


Tons. 

2037  -  |  =  1133  tons, 


the  capacity  of  the  ship.  Again,  we 
may  perhaps  be  able  to  learn  something 
from  the  rule  laid  down  on  page  45, 
when  applied  to  a  body-plan,  filled  out 
as  Plate  5.  Taking  the  dimensions 
of  this  plate  from  the  tables,  we  have 
length  of  keel  100  feet,  and  of  load-line 
116  feet,  area  of  dead-flat  272  square 
feet.     The  formula  may  be  thus — 

Length 
Length    between  Mean      Area  of 

keel,     pcrpendic.  length,    dead-flat  Tons. 

100+116=2164-2=L0Sx272=2937G-^47=625 

The  actual  displacement  is  620  tons. 
Thus  the  reader  will  discover,  as  we 
have  before  remarked  on  page  45,  that 
no  invariable  rule  can  be  given  which 
will  either  furnish  the  displacement  or 
capacity  with  any  considerable  degree 
of  accuracy.  The  divisor  that  will  ap- 
ply on  all  vessels  of  nearly  the  same 
shape,  will  not  apply  to  the  vessel 
shown  on  Plate  5,  as  will  be  seen  by  re- 
ferring to  page  45.  The  highest  num- 
ber there  given  for  merchant  ships  is 
46;  this  applies  to  sharp  ships  of  the 
usual  form.  This  vessel,  as  will  be 
perceived,  has  a  low  centre  of  effort, 
consequent  upon  her  being  narrow,  and 
having  an  easy  bilge.  It  will  be  re- 
membered also,  that  vessels  having  a 
low  centre  of  effort,  have  but  little  sta- 
bility,   without    ballast.     The   import- 


ance is  at  once  manifest  of  knowing 
how  to  determine  not  only  the  displace- 
ment but  the  stability  of  vessels.  Thus 
we  see,  that  in  the  draught  we  arc  con- 
sidering, spread  out  on  the  board  before 
us,  Ave  can  determine  nothing  in  rela- 
tion to  the  stability;  although  we  may 
have  good  dimensions  for  the  same,  yet 
the  shape  may  be  such  as  to  counteract 
all  that  we  may  have  gained  by  good 
dimensions.  Assuming  that  the  dis- 
placement and  stability  is  what  we  re- 
quire, we  may  proceed,  after  running  in 
all  the  parallel  or  water-lines  in  the  half- 
breadth  plan,  to  striking  lines  parallel 
to  the  middle  or  side-line  in  the  body- 
plan,  as  shown  in  Plate  5.  The  line 
next  to  the  middle-line  will  be  num- 
bered 1,  and  the  numbers  will  in- 
crease as  we  advance  outward  towan 
the  side.  The  distance  from  one  t( 
the  other,  or  the  space  between  them, 
should  be  regulated  by  the  water-lines 
in  the  sheer-plan  ;  that  is  to  say,  the 
water-lines  in  the  sheer-plan  show  tin 
distance  these  vertical  lines  are  spaced 
apart  in  the  body-plan.  The  same  ar- 
rangement may  extend  to  the  half- 
breadth  plan,  showing  the  lines  paral- 
lel to  the  middle-line,  and  at  right  an- 
gles with  the  frames  ;  they  arc  usualh 
called  section-lines.  The  reason  for 
spacing  them  thus  is,  that  when  we 
lay  down  a  ship,  we  find  it  advanta- 
geous to  have  no  more  lines  than  is  ab- 


MARINE    AND    NAVAL    ARCHITECTURE 


169 


solutely  necessary  ;  and  by  making  use 
of  the  water-lines  for  section-lines,  we 
avoid  the  necessity  of  having  other 
lines.  These  lines  are  shown  in  the 
three  plans — sheer,  half-breadth,  and 
body -plans,  but  principally  required 
in  the  sheer-plan.  Their  utility  will 
be  discovered  by  referring  to  Plate 
4.  The  shape  of  those  lines  is  obtain- 
ed from  the  body-plan  by  taking  the 
distance  on  a  slip  of  paper  from  the 
base-line  to  each  frame  on  the  first 
section-line ;  mark  also  against  each 
spot,  the  number  of  the  frame  to  which 
it  belongs;  after  taking  off  all  the  frames 
on  the  line  on  which  we  begin,  we  may 
apply  the  height  to  each  frame  in  the 
sheer-plan,  between  the  dead-flat  and 
the  post  in  the  after-body,  and  between 
the  stem  and  dead-flat  in  the  fore-body. 
After  we  have  completed  the  settings- 
off,  we  may  apply  the  batten  to  the 
spots ;  the  after-end  running  out  fair, 
the  end  of  the  batten  forward  will  ter- 
minate on  a  spot  found,  by  squaring 
up  the  intersection  of  the  same  line 
(from  the  half-breadth  plan)  with 
the  rail  of  the  same — the  sheer-plan 
already  showing  the  height  of  the 
end,  when  the  distance  forward  is  de- 
termined, or  as  shown  in  Plate  5,  by 
tin1  ending  on  the  curve  showing  the 
height  of  the  rail.  The  same  arrange- 
ment docs  not  answer  the  purpose  aft, 
inasmuch  as  the  projection  of  the  stern 


partially  interferes,  although  the  line 
will  finally  end  on  the  taffrail,  as  in  Plate 

4.  We  have  said  that  the  aft-end  of 
the  batten  should  be  carried  out  fair, 
aft  of  the  last  frame  in  the  after-body, 
provided  at  the  same  time,  the  first  sec- 
tion-line by  so  doing  will  end  on  the 
cross-seam ;  and  if  we  adhere  to  the 
old  method  of  having  the  cross-seam 
level,  and  the  transom  square  from  the 
middle-line  on  the  back,  the  sections 
will  all  end  in  the  corner.  Those 
lines,  it  will  be  readily  perceived,  repre- 
sent vertical  planes  running  lengthwise 
through  the  ship  parallel  to  the  middle- 
line.  The  half-breadth  and  body-plan 
may  be  regulated  with  a  very  consid- 
erable degree  of  accuracy  by  those 
lines. 

It  will  be  seen,  by  referring  to  Plate 

5,  that  the  first  height  or  the  wale,  al- 
though ending  on  the  cross-seam,  does 
not  end  in  the  corner  as  in  Plate  4. 
And  we  will  here  remark,  that  Plate  4 
shows  the  same  line  on  a  plane  that 
Plate  5  shows  on  the  ship,  and  this  is 
the  reason  why  so  little  pains  is  taken 
to  regulate  the  sheer  from  the  sirmarks, 
instead  of  running  a  rope  around  a 
ship,  as  is  usually  done.  The  same  dis- 
crepancy exists  forward,  but  the  de- 
parture is  not  so  great  on  the  bow. 
The  careful  observer  will  see.  that  al- 
though the  opening  between  the  first 
and   second  sheer-lines  on  dead-flat  in 


22 


170 


MARINE   AND    NAVAL    ARCHITECTURE. 


Plate  5,  are  3  feet  S  inches  apart,  and 
on  the  cross-scam  line  measured  in  the 
same  mamicr.  are  only  1  foot  11  inches 
apart,  showing  an  actual  taper  of  1  foot 
9  inches,  yet  the  opening  is  actually 
largest  aft  when  measured  hy  the  eye. 
Again,  it  will  be  seen  that  in  the  sheer- 
plan  of  Plate  4,  the  opening  between 
the  first  and  second  sheer-lines  taper 
enough  to  be  readily  discovered,  yet 
when  the  eye  drops  down  to  the  half- 
breadth  plan  we  discover  that  the  wale 
on  the  ship  cannot  run  around  to  the 
stern-post,  although  it  does  on  the 
draught.  Hence  it  is  plain  that  the 
draught  and  the  ship  do  not  agree  ;  and 
the  question  at  once  arises,  why  is  this 
discrepancy  ?  It  will  appear  quite 
plain,  that  the  thickness  of  the  plank 
midships  neither  elevates  or  depresses 
the  sheer,  though  the  plank  may  be  six 
inches  in  thickness,  while  at  the  end 
the  flare  and  twist  causes  the  outer 
edge  of  the  plank  to  drop  below  the 
inner  edge  ;  and  the  edge  next  to  the 
timbers  should  range  above  as  much  as 
is  lost  by  the  thickness  of  the  plank 
projecting  in  a  diagonal  direction,  else 
the  outside  of  the  plank  will  range  be- 
low the  original  design.  But  this  is  not 
all ;  although  the  model  and  draught 
show  the  ship  as  she  should  appear 
when  the  plank  is  on,  it  is  evident  that 
the  additional  height  required  should 
be  added  before  marking  the  sheer-lines 


in  with  ink  ;  this  may  be  done  by  add- 
ing- the  thickness  of  the  plank  (which 
should  always  be  somewhat  less  on  the 
ends  than  midships)  to  the  cross-seam 
line  ;  then  level  out  a  line  to  this  thick- 
ness from  the  inside  at  the  sheer-line 
to  the  outside  of  the  plank,  and  mitre 
a  line  showing  the  seam  into  the  tim- 
bers ;  its  intersection  will  be  the  proper 
height  on  the  cross-seam  line  for  the 
wale  or  first  height.  The  discrepanc 
at  the  second  height  is  not  so  great,  in 
consequence  of  there  being  much  less 
twist ;  the  same  provision  will  have 
the  same  effect.  The  same  operation 
should  extend  to  several  frames  for- 
ward of  the  cross-seam,  and  on  the  bow 
in  like  manner.  Whatever  the  flare 
of  the  bow  in  the  thickness  of  the 
plank  drops  the  sheer,  the  line  should 
be  raised  that  amount  before  inking  in 
the  sheer-lines  in  the  draught — their 
ending  on  the  stern  has  not  yet  been 
determined.  We  may  see  in  Plate  4 
the  section-lines  continued  above  the 
cross-seam  to  the  taffrail,  the  round  of 
the  stern  showing  those  nearest  the 
outside  to  be  forward  of  those  nearest 
the  centre.  This  course  is  not  gene- 
rally pursued  either  on  the  draught  or 
on  the  floor.  Again,  in  Plate  5  w 
may  seethe  section-lines  ending  on  the 
cross-seam  line,  leaving  the  space  above 
a  blank,  or  as  the  ship  is  found  to  be 
after  the  frames  are  all  raised. 


;t 

i 


MARINE    AND    NAVAL    ARCHITECTURE. 


171 


We  have  already  shown  that  the 
sheer-lines  may  end  temporarily  on  the 
centre  counter-timber  ;  we  may  deter- 
mine the  amount  of  round,  or  how 
much  higher  the  taffrail  should  be  at 
the  centre  than  at  the  side  of  the  ship  ; 
this  being  done,  and  the  number  of 
inches  set  up  square  from  the  sheer- 
line,  we  may  run  up  the  centre  counter- 
timber  to  the  required  height ;  this 
point  may  now  be  squared  down  to  the 
middle-line  of  half-breadth  plan,  and  the 
round  thwart-ship,  or  across  the  stern, 
may  then  be  also  determined  ;  and 
where  the  sheer-line  showing-  the  rail 
in  the  half-breadth  plan  crosses  the  line 
for  the  round  of  the  stern,  that  point 
may  be  squared  up  to  the  sheer-plan, 
and  is  the  ending  of  the  third  breadth 
in  the  sheer-plan,  or  the  corner  of  the 
stern  at  the  rail.  It  is  not  necessary 
that  the  first  and  second  breadths  should 
terminate  in  any  line  across  the  stern. 
The  arch-board  may  be  set  off  on  the 
centre  counter-timber,  and  its  round 
determined  in  the  same  manner  as  that 
of  the  rail,  by  squaring  the  centre  down 
to  the  half-breadth,  and  giving  it  the 
same  or  more  round  than  the  rail.  If 
the  stern  has  no  twist,  and  the  arch- 
board  has  the  same  round  as  the  rail, 
the  lines  on  the  stern  in  the  half-breadth 
should  be  parallel  to  the  line  showing 
the  taffrail;  if,  on  the  contrary,  the 
stern  has  more  or  less  twist,  the  second 


breadth  may  be  continued  across  the 
stern,  as  in  the  half-breadth  plan  of 
Plate  4  ;  and  its  intersection  squared 
up  to  the  sheer-plan.  The  corner  of 
the  stern  may  now  be  shown  by  draw- 
ing- a  line  touching  the  two  spots  al- 
ready furnished,  and  continuing  as  low 
as  the  upper  edge  of  the  arch-board ; 
from  this  point  it  may  be  continued 
down,  out  of  wind  with  the  centre  of 
the  stern,  or  the  same  proportionate 
amount  of  twist  may  be  continued  and 
obtained  by  running  in  a  temporary 
sheer-line,  or  to  remain  if  deemed  ne- 
cessary. If  the  cross-seam  has  any 
rise,  as  in  Plate  3,  4  and  5,  the  outer 
section-line,  as  in  Plate  4,  will  give  a 
spot  for  the  quarter  ;  and  another  sec- 
tion-line may  be  run  in,  which  will  fur- 
nish all  the  spots  that  we  may  require. 
It  is  not  necessary  to  show  how  to  run 
in  an  additional  sheer  or  section-line  ; 
the  same  course  must  be  pursed  with 
all  lines  of  the  same  denomination, 
whether  temporary  or  permanent  ;  and 
having  been  shown,  it  is  not  necessary 
to  repeat  the  operation  ;  what  lines  w  e 
may  have  found  necessary  to  run  across 
the  stern,  between  the  arch-board  and 
rail,  will  not  be  required  for  permanent 
use,  and  must  not  be  inked.  The  stern 
for  the  present  requires  no  nunc  lines 
running  across,  either  in  the  half- 
breadth  or  sheer-plan,  than  the  rail, 
arch-board,  and  cross-seam.   The  cabin 


172 


MARINE    AND    NAVAL    ARCHITECTURE. 


windows  may    be   shown  in    the    half- 
breadth  plan,  also    in    the    body  plan. 
We  mav  before  proceeding  farther,bend 
a  batten  at  the  heads  of  the  frames,  cut- 
ting the  exact  crossing  of  the   frame 
with  its  own  leveled   height,   stricken 
across   the    body   plan  ; — one    end  of 
this   line    in    the   fore-body   is   at    the 
height  of  the  dead-flat  frame,  and  the 
other  at  the  height  of  the  margin-line 
in  the   sheer-plan,  set  up  in   the  body 
as  taken  from  the  sheer-plan.     In  the 
after-body  the  line  begins  at  the  same 
height  as  in   the    fore-body,   viz.,  the 
dead-flat  frame,  and  continues  cutting 
the  heads  of  the  frames  until  it  reaches 
the  cross-seam  height,  from  whence  it 
crosses  the  stern  and  ends  on  the  mid- 
dle-line, at  the  height  of  the  centre  of 
the  taffrail,  as  in  Section  4  of  Plate  2, 
and  as  shown  on  the  stern  in  the  sheer- 
plan,  Plate  4.     We  may  next  proceed 
to   strike    in  the  intermediate  frames, 
both    in    the    sheer    and    half-breadth 
plans,  and  take  off  and  sweep  them  in 
the    body  plan.     It  may  be   fairly  as- 
sumed   that    the  draught    is    proven  ; 
although  there  are  more  lines  yet  re- 
quired to  complete  it  in  all  the  plans, 
yet  the  water  and  section-lines  agree- 
ing with  the  frames,  and  each  making 
fair  lines,  there  can  be  little  doubt  but 
that  the  lines  will  prove  in  every  part 
if  sufficiently  near  each   other.      The 
operation  on  the  draught   requires  to 


be  somewhat  different;  on  the  latter 
the  diagonals  are  not  required  for  proof 
lines,  although  sometimes  used  ;  but  in 
the  operations  on  the  floor,  the  arrange- 
ment is  made  as  soon  as  the  water- 
lines  are  proven,  for  by  arranging  the 
angles  of  the  diagonals  in  the  body  plan 
to  suit  the  length  of  timber  the  builder 
may  have,  the  butts  are  arranged  so 
that  the  shape  of  the  timbers  may  not 
be  very  difficult  to  find.  This  operation 
requires  some  considerable  degree  of 
skill  to  regulate  the  various  crooks,  that 
there  may  be  no  timbers  that  cannot  be 
obtained,  be  the  shape  of  the  vessel 
what  it  may.  We  have  not  designed 
the  draught  to  exhibit  anything  more 
than  the  manner  of  performing  the 
operation,  of  showing  the  effect  of  a 
tapered  sheer,  and  of  arranging  the  sev- 
eral plans  on  one  entire  plane;  where- 
as the  operations  of  the  floor  by  sec- 
tions, showing  the  ship  in  two  or  three 
lengths,  could  not  (it  was  presumed)  be 
as  easily  understood  without  this  con- 
necting link  ;  nor  was  it  designed  to 
put  in  all  the  lines  belonging  to  any  one 
section  of  the  ship,  throughout  the  en- 
tire work,  for  the  evident  reason  that 
we  have  not  undertaken  to  exhibit  pic- 
tures, but  to  illustrate  not  only  princi- 
ples, but  the  manner  of  working  by 
them;  hence  it  is  evident,  that  the 
fewer  the  number  of  lines  beyond  what 
is  necessary  to  show  that  for  which  the 


MARINE    AND    NAVAL    ARCHITECTURE. 


173 


engraving  is  designed,  the  more  easily 
understood. 

Having  shown  the  effect  of  shape, 
first,  from  the  model  in  its  rotundity, 
and  following  this  by  expositions  on 
the  floor,  in  sections  adapted  to  the 
length  of  the  mould-loft,  and  again 
showing  the  general  outline  of  the  sev- 
eral plans  on  the  draught,  from  which 
we  shall  now  deduce  some  leading  prin- 
ciples that  should  govern  all  construc- 
tors of  vessels  designed  to  navigate  the 
ocean,  it  will  be  discovered,  that  on  Plate 
7  we  have  shown  the  form  of  the  in- 
scribed line  of  flotation  the  draught 
above  would  delineate  when  immersed 
to  her  load-line,  and  careened  fifteen 
degrees  from  the  upright  or  position  of 
rest  ;  the  two  sides  being  marked,  it  will 
readily  be  discovered  that  there  is  a 
material  difference  in  their  form  at  the 
ends,  although  of  equal  breadth  mid- 
ships. Though  we  have  never  seen 
this  plan  appended  to  a  draught,  it  does 
not  follow  that  it  should  not  be.  The 
builder  or  constructor  who  does  not 
know  what  is  the  shape  of  the  careen- 
ed line  of  flotation  of  the  ship  he  is 
about  to  build,  does  not  know  as  much 
about  her  steering  qualities  as  he  sup- 
poses, however  well  he  may  be  satisfied 
in  his  own  mind  of  her  performances 
in  this  particular.  It  will  be  seen  that 
the  lee-line  of  flotation  is  fuller  both 
forward  and  aft  than  the  weather-line, 


and  although  this  line  on  cither  side 
only  determines  the  course  of  the  fluid 
at  the  surface,  it  is  an  index  to  the 
shape,  both  above  and  below  this  in- 
clined line  of  flotation.  Those  who 
will  take  the  trouble  to  compare  this 
inclined  form  of  water-line  with  that  of 
any  of  the  European  packet-ships  out 
of  this  port,  will  find  that  there  is  much 
less  difference  than  can  be  found  among 
freighting-ships,  subject  of  course  to 
exceptions,  which  are  very  rare. 

It  must  be  apparent  to  the  thinking- 
man,  that  with  a  difference  in  the  form 
of  the  weather  and  lee-lines  of  flotation, 
as  in  Plate  7,  the  ship  will  carry  a 
weather-helm.  Seamen  find  that  the 
water  acts  with  more  force  on  the  rud- 
der of  a  ship  about  half  way  between 
the  greatest  immersed  line  of  flotation 
and  the  base-line,  than  it  does  on  other 
parts  ;  and  the  reason  will  appear  ob- 
vious, for  it  is  only  at  that  part  of  the 
rudder  that  the  lee-lines  of  the  ship 
form  a  suitable  conductor  to  the  rudder 
with  the  least  disturbance.  The  whirl- 
ing impulse  imparted  to  the  globular 
particles  of  fluid,  show  that  they  can- 
not be  restored  to  their  buoyancy  by 
any  sudden  change  of  direction.  When 
the  ship  is  careened  about  fifteen  de- 
grees from  the  upright  position,  it  al- 
ters the  course  of  the  water  at  the  sur- 
face of  the  anterior  as  well  as  that  of 
the  posterior  part  of  the  ship,  and  when 


174 


MARINE    AND    NAVAL    ARCHITECTURE 


thus  inclined,  the  distance  on  the  line 
of  Hotation  from  the  greatest  trans- 
verse section  to  the  rudder  being  much 
shorter  on  the  windward  than  on  the 
leeward  side,  it  follows  as  a  conse- 
quence, that  the  water  comes  directly 
to  the  rudder  on  the  windward  side  in 
a  steady  current,  while  on  the  leeward 
side  it  acts  precisely  as  it  does  in  the 
river  where  the  current  or  tide  sweeps 
by  the  end  of  a  pier  with  great  force, 
while  below  the  pier,  and  between  its 
end  and  the  shore,  the  current  is  setting- 
up,  or  in  an  opposite  direction;  the 
consequence  is,  that  the  cavity  between 
the  quarter  and  the  rudder  is  filled  up 
from  below  on  the  lee-side.  We  have 
measured  some  fine  ships  in  other  re- 
spects, sailing  out  of  this  and  other 
ports  of  the  United  States,  that  had 
eight  feet  of  difference  under  the  quar- 
ter in  their  weather  and  lee-lines  of 
flotation. 

It  must  be  apparent  that  the  pres- 
sure consequent  upon  the  current 
(formed  by  the  moving  ship)  on  the  two 
sides  of  the  rudder,  being  unequal  when 
the  helm  is  midships,  the  lee-bow  being 
also  the  fullest,  which  tends  to  push  it 
around  to  windward,  when  the  ship  is 
brought  to  the  wind, and  to  avoid thisthe 
helmsman  must  keep  his  helm  up  until 
the  two  forces  are  equal,  when  the  ship 
is  again  on  her  course.  The  effect  of 
this  inequality  on  the  bow  is  to  bring  a 


vessel  to  the  wind;  the  surface  on  the 
leeward  side  of  the  keel  being  the 
greatest,  it  follows  that  the  pressure 
against  the  lee-side  is  also  the  greatest, 
and  to  be  relieved,  the  bow  seeks  an 
equilibrium  by  inclining  to  the  wind- 
ward side,  where  there  is  less  resist- 
ance. Careening  a  ship  of  the  ordi- 
nary model  has  the  same  effect  upon 
the  steering  qualities,  that  it  would  have 
to  move  the  stern-post  aside  one,  two, 
or  three  feet  from  the  centre  of  the 
vessel,  and  terminating  all  the  lines 
there,  and  then  sailing  her  in  an  up- 
right position.  Why  is  it  that  we  do 
not  perceive  any  difference  in  the  scud- 
ding-ship,  or  that  she  does  not  require 
the  helm  on  one  side  more  than  the 
other?  The  reason  is  at  hand — the 
pressure  on  the  two  sides  of  the  rudder 
is  equal.  Hence  the  reason  why  mari- 
ners complain  of  vessels  steering  bad 
before  the  wind  ;  they  veer  from  their 
course  until  they  receive  the  wind  from 
the  quarter  ;  this  causes  them  to  ca- 
reen, and  as  soon  as  an  inclination 
takes  place,  the  water  ceases  to  act 
with  the  same  amount  of  force  on  the 
leeward  side,  and  acts  with  increased 
force  on  the  windward  side  ;  conse- 
quently she  is  steady  for  the  moment, 
but  as  soon,  as  the  helmsman  brings 
her  to  her  course,  she  perforins  the 
same  freaks  again. 

We  might  point  our  readers  to  ships 


MARINE    AND    NAVAL    ARCHITECTURE, 


175 


in  different  parts  of  the  United  States, 
calling  many  by  name,  upon  which 
these  deformities  would  be  found,  but 
it  is  not  the  province  of  marine  archi- 
tects to  depreciate  the  value  of  any 
man's  property  by  pointing  out  its  de- 
fects in  a  work  of  reference  like  this ; 
naval  architects  can  do  so  with  the 
utmost  propriety,  inasmuch  as  an  ex- 
hibition of  the  defects  of  government 
vessels  injures  no  one.  The  shape  of 
the  ship  shown  in  the  draught,  Plate  7, 
is  such,  that  the  two  lines  of  flotation 
would  cause  the  ship  to  steer  remarka- 
bly easy,  and  with  less  of  the  weather- 
helm  than  is  commonly  met  with  in 
sailing-ships,  although  the  first  water- 
line  is  somewhat  fuller  than  is  usual  ; 
and  if  a  model  were  made  by  this 
draught,  a  majority  of  builders  would 
tell  us  that  she  would  not  steer ;  and 
when  public  opinion  is  prepared  to  look 
naked  truths  in  the  face,  it  will  be  found 
that  the  very  shape  that  has  been  repu- 
diated on  account  of  bad  steering,  is 
the  shape  above  all  others  that  steers 
the  best. 

It  will  be  observed,  from  what  has 
been  shown,  that  it  is  the  half-breadth 
plan  that  delineates  the  form  of  vessels 
in  all  the  variety  of  positions  that  may 
be  requisite  for  adapting  them  to  all  the 
varied  circumstances  to  which  sea- 
going vessels  in  particular  are  subject. 
The    direction   of  the   vessel   through 


the  water  is  longitudinal,  and  all  that 
can  pertain  to  the  development  of  the 
best  form  for  speed,  burthen,  or  per- 
formance, must  be  shown  by  this  plan  ; 
not  only  the  several  sheer  and  water 
or  parallel-lines,  whether  showing  the 
vessel  upright  or  inclined,  but  the  diago- 
nal-lines are  also  shown  in  their  rotun- 
dity ;  and  from  no  other  plan  can  we 
form  a  just  conception  of  the  actual 
shape  of  the  vessel  when  on  a  plane. 
and  not  lifted  up  by  the  laws  of  geo- 
metrical perspective.  However  im- 
portant the  half-breadth  plan  may  be, 
the  body  plan  is  not  entirely  destitute 
of  claims  upon  our  attention.  Al- 
though no  just  conception  can  be  form- 
ed of  the  shape  of  the  vessel  from  this 
plan,  yet  it  cannot  be  dispensed  with, 
while  the  present  method  of  construct- 
ing vessels  meets  with  popular  favor. 
The  actual  form  of  all  the  transverse 
sections  may  be  shown  in  this  plan, 
and  the  bevellings  of  the  timbers  may 
also  be  obtained.  The  body  plan  of  the 
draught,  shown  in  Plate  7,  represents 
the  frames  falling  within  each  other, 
as  they  would  appear  to  the  eye  of  an 
observer  were  he  to  take  a  position 
astern  of  the  ship,  his  eye  in  line  with 
the  keel  transversely,  and  with  the  load- 
line  vertically.  Assuming  the  after- 
body from  0  on  the  larboard  side  to  be 
left  out,  this  view  would  show  the  star- 
board  quarter  and   the  larboard  bow  : 


176 


MARINE   AND    NAVAL    ARCHITECTURE. 


or  if  the  eye  of  the  observer  were  loca- 
ted forward,  with  the  starboard  bow 
taken  down,  the  result  would  be  the 
same. 

Having  carried  the  draught  through 
a  second  proof,  we  will  leave  it  for  the 
present,  and  again  resume  our  position 
in  the  mould-loft.     We  left  the  floor  at 
page  140  to  illustrate  the  true  princi- 
ples of  sheering  vessels,  which   could 
not  be  done  satisfactorily  without  the 
aid  of  the  draught,  from  which  some 
other  important    principles  have    also 
been   deduced ;   and  now  before  enter- 
ing upon  the  delineation    of  a  second 
proof  on  the  floor,  we  will  add  all  that 
will   be    necessary   upon  a  subject  al- 
ready   broached.     Having    shown    on 
page  128  that  the  dead  woods  both  for- 
ward and  aft  should  be   of  sufficient 
height  to  cover  the  heels  of  the  cants, 
we  will  first  take  up  the  subject  of  seat- 
ing the  floors.     Having    shown  what 
the  bearding-line  is,  and  how  it  is  ob- 
tained, we  shall  find  that  by  cutting  in- 
side of  the  side-line  to  obtain  the  thick- 
ness of  the  plank,  we  cause  not  only 
the  bearding-line  to  rise  above  the  base, 
but  throats  of  the  floor-timbers  also  to 
rise  higher  above  the  base,  in  order  that 
we  may  obtain  the  same  scantling  size 
for  the  heel  of  the  first  futtock  when 
measured  square    from    the   moulding 
edge  of  the  timbers.     Hence  it  is  plain 
that  we  must  either  have  the  scantling 


less  at  the  ends  of  the  ship  than  in  the 
centre,  or  have  the  throats  of  the  floors 
higher  forward  and  aft  than  at  dead- 
flat  ;  and  inasmuch  as  there  can  be  no 
prominent  objection  to  the  longitudinal 
hollow  to  the  throats  of  the  floors, 
while  there  are  objections  to  reducing 
the  scantling  size  of  the  timbers  before 
we  pass  the  floors  or  square-framesj 
(after  which  it  may  be  reduced  to  ad- 
vantage.) With  this  arrangement  it 
follows  that  the  floors  are  deeper  in  the 
throat  at  the  forward  and  after  square- 
frame  than  at  dead-flat,  which  surplus 
size  is  not  required  for  strength  ;  and, 
as  it  is  required  above  and  not  below , 
it  at  once  becomes  apparent  that  we 
add  strength  and  security  by  taking  t  he 
surplus  size  from  the  breech  of  the 
floors  over  that  of  the  dead-flat  from 
below,  and  filling  up  the  space  with 
keel  or  dead  wood :  consequently  the 
line  showing  this  rise  or  additional  size 
of  keel  would  be  parallel  to  the  throats 
of  the  floor,  and  as  the  floor  may  be  let 
down  by  cutting  the  wood  out  of  the 
floor  or  the  keel,  we  prefer  cutting 
the  floor,  and  are  not  alone  in  this  par- 
ticular. This  line  has  been  called  the 
cutting-down-line,  and  its  height  above 
the  base  must  be  known  from  the  loft 
before  the  keel  can  be  finished.  The 
first  questions  in  obtaining  it  are  these 
— what  is  the  throating  of  the  floors  at 
dead-flat  .'     and    what    will    the    same 


MARINE    AND    NAVAL    ARCHITECTURE. 


177 


scantling-  at  the  heel  of  the  first  fnttock 
on  dead-flat  give  for  throating  at  the 
forward  and  after  floor?  See  Plate  8. 
Making  a  spot  at  each  of  the  three 
frames  above  the  base  in  the  sheer-plan, 
and  one  in  the  middle  of  the  fore  and 
after-body,  thus  we  have  five  spots 
showing  the  height  of  the  throats  of  the 
floor,  to  which  a  batten  may  be  ap- 
plied and  made  fair,  continuing-  out  fair 
to  the  stem  and  post ;  we  may  now 
run  another  parallel  to  this,  cutting-  the 
base  at  dead-flat,  and  extending  from 
the  fore-side  of  the  forward  floor  to  the 
aft-side  of  the  after  floor  :  this  line  re- 
presents the  seats  of  the  floors,  and  may 
be  formed  on  the  keel,  or  placed  on  the 
keel  in  an  additional  piece.     In  running 


the  line  for  the  throating  of  the  floors, 
we  should  have  reference  to  the  keelson, 
and  not  get  so  much  hang  to  the  line  that 
we  will  be  unable  to  get  a  keelson  piece 
that  will  set  down,  as  the  keelson  should 
run  out  and  form  part  of  the  dead  wood, 
and  what  additional  dead  wood  we  may 
require,  may  be  placed  above  the  keel- 
son. It  is  seldoYn  however  that  more 
is  necessary  forward  than  a  large  stem- 
son  or  knee,  and  if  the  stem  has  a 
very  considerable  rake,  straight  timber 
will  answer  every  purpose,  and  be 
equally  as  strong,  if  so  arranged  as  to 
cause  both  ends  to  have  the  same  bevel, 
and  we  may  fill  up  to  any  required 
height  in  the  same  manner. 


89 


178 


MARINE    AND    NAVAL    ARCHITECTURE 


CHAPTER    VI. 

Diagonal  Lines — Their  Use — Mathematical  Demonstrations  in  Modelling  by  Diagonal  and  Water-Lines, 
discovered  by  the  Author — Their  Superiority  over  the  Present  Mode. 


Iii  Europe  it  has  been  the  practice 
to  make  use  of  two  kinds  of  water- 
lines,  not  only  on  the  draught,  but  on 
the  floor  of  the  loft — the  one  parallel 
to  the  base-line,  the  other  parallel  to 
the  inscribed  line  of  flotation.  This 
practice  has  been  coeval  with  that  of 
so  forming  the  bodies  of  vessels  as  to 
cause  them  to  draw  more  water,  or  to 
swim  deeper  aft  than  forward  As  a 
consequence,  the  form  of  any  two  lon- 
gitudinal lines  that  had  the  same  alti- 
tude midships,  differed  in  proportion  to 
the  difference  of  the  draught  of  water 
at  the  two  ends  of  the  vessel ;  and  if  a 
displacement  equivalent  to  the  weight 
of  the  vessel  were  obtained  below  a  line 
parallel  to  the  base,  (while  the  vessel 
was  leaner  aft  than  forward  of  the  lon- 
gitudinal centre,)  it  was  found  that  the 
inscribed  line  of  flotation  was  not  shown 
on  the  draught.  If  the  vessel  drew 
more  water  aft  than  forward,  the  line 
of  flotation  was  fuller  aft,  and  easier 
forward  than  the  water-line  shown  on 
the  draught.  Experience,  however, 
has  taught  mechanics  in  one-half  of  the 


world  at  least,  that  a  form  of  construc- 
tion requiring  a  very  considerable  dif- 
ference in  the  draught  of  water  is  no 
advantage  to  the  performing  qualities 
of  such  vessel ;  hence  the  reason  why 
we  find  the  vessels  of  more  modern 
build  drawing  nearly  an  equal  draught 
of  water.  Even  the  far-famed  Balti- 
more clippers,  some  of  which  drew 
sixteen  feet  of  water  aft,  and  eight  feet 
forward,  are  brought  within  from  one 
to  two  feet  of  difference  in  the  draught 
of  water  of  the  two  ends  ;  and  the 
time  is  at  hand  when  inches  will  be 
substituted  for  feet  in  this  particular. 
Thus  we  perceive  that  two  sets  of 
water-lines  are  no  longer  rendered  ne- 
cessary, either  on  the  draught  or  on 
the  floor.  Diagonal  lines  have  been 
designed  to  answer  a  three-fold  pur- 
pose— First,  to  show  the  boundaries 
of  oblique  planes  passing  through  the 
ship  longitudinally,  and  meeting  the 
middle-line  its  entire  length,  parallel  to 
the  base-line.  Their  second  use  has 
been  found  in  the  aid  furnished  in  ar- 
ranging the  lengths  of  the  timbers  form- 


MARINE    AND    NAVAL    ARCHITECTURE. 


17S 


lug  the  frame  of  the  ship  ;  and  the 
third  particular  in  which  they  have 
been  found  useful,  is  for  proving  the 
water-lines,  and  for  bevelling  spots,  or 
convenient  and  suitable  localities  for 
applying  the  bevels. 

The  position  of  the  diagonal  lines  in 
the  body  plan  where  they  are  first 
drawn,  is  not,  however,  arbitrary,  be- 
cause it  has  reference  to  two  consid- 
erations in  particular — the  length  of  the 
timbers,  and  their  shape.  It  formerly 
was  the  custom,  and  is  still,  to  some 
extent,  to  place  the  ribbands  by  those 
lines,  but  experience  has  shown  that  it 
is  not  absolutely  necessary ;  although 
the  ribband  would  be  more  likely  to  fit 
the  timbers  upon  a  diagonal  line  than 
elsewhere,  because  of  its  being  at  the 
identical  spot  where  the  body  was 
proved,  and  where  the  bevel  was  ap- 
plied, and  so  far  as  this  goes,  it  is  the 
most  suitable  place  ;  but  if  the  neces- 
sary pains  were  taken  in  proving  and 
fairing  the  bodies  on  the  floor,  and  an 
equal  amount  of  care  taken  in  mould- 
ing and  bevelling  the  timber,  it  would 
make  little  difference  where  the  rib- 
bands were  placed  for  regulating  and 
keeping  the  ship  to  her  proper  place 
when  raised.  Plate  9  will  illustrate 
the  manner  of  arranging  the  diagonals 
in  the  body  plan.  It  was  formerly  the 
custom  both  in  draughting  and  in  lay- 
ing down  vessels  to  expand  the  diago- 


nals when  taken  off" in  the  direction  in 
which  the  line  run  in  the  body  plan; 
and  this  mode  is  to  some  extent  yet  in 
use.  It  may  answer  the  purpose  very 
well  where  a  sufficiency  of  floor  room 
can  be  obtained,  but  cannot  be  adopt- 
ed where  floor  room  is  limited,  as  in 
this  city,  and  in  most  private  ship-yards. 
It  was  from  the  diagonals  swept  in  this 
manner  that  the  bevels  were  obtained 
from  the  half-breadth  plan  before  it 
was  discovered  that  they  might  be  taken 
with  more  accuracy  from  the  body  plan. 
The  lines  were  taken  off  according  to 
the  old  method,  by  taking  the  distances 
from  the.  middle-line  in  the  body  plan 
(in  the  direction  of  the  diagonals)  to  the 
frame  about  to  be  transferred,  and  set- 
ting off  the  distance  thus  taken  on  the 
same  frame  in  the  half-breadth  plan. 
This,  as  it  will  be  readily  perceived, 
causes  the  lines  to  extend  further  out 
from  the  middle-line  in  the  half-breadth 
than  any  of  the  lines  taken  off  horizon- 
tally, particularly  those  in  the  vicinity 
of  the  bilge  of  the  vessel.  For  the  end- 
ing  of  those  lines  when  taken  in  the 
angular  direction,  the  height  must  be 
taken  from  the  base-line  in  the  body 
plan  to  the  intersection  of  the  diagonal 
with  the  side-line;  let  this  height  be 
transferred  to  the  sheer-plan,  and  mark- 
ed on  the  bearding-line,  and  from 
thence  squared  down  to  the  middle- 
line  of  the   half-breadth  plan,  and   set- 


ISO 


MAIIINE    AND    NAVAL    ARCHITECTURE. 


ting  off  the  thickness  of  the  plank  in- 
ward from  the  side-line  in  the  body 
plan,  as  shown  by  the  dotted  line  in 
Plate  9.  The  height  of  the  point  at 
which  the  diagonal  crosses  this  dotted 
line,  must  also  be  taken,  and  set  up  on 
the  margin-line  of  the  stem  or  post, 
(provided  the  line  we  are  now  ending 
does  not  come  above  the  head  of  the 
post,)  from  whence  it  must  be  squared 
down  with  the  former  to  the  middle- 
line  of  the  half-breadth  ;  take  the  dis- 
tance from  the  middle-line  of  the  body 
plan  in  the  direction  of  the  diagonal  to 
the  dotted  line,  (which  shows  the  thick- 
ness of  the  plank.)  and  set  this  off  from 
the  middle-line  of  the  half-breadth  upon 
the  forward  spot  just  squared  down  and 
marked  a  in  the  half-breadth,  and  the 
distance  from  the  middle  to  the  side- 
line in  the  direction  of  the  diagonal ; 
set  this  distance  oft'  from  the  middle- 
line  of  the  half-breadth  on  the  after  spot 
marked  b.  It  will  be  discovered,  that 
this  operation  makes  the  stem  and 
plank  appear  thicker  than  they  really 
are;  but  when  it  is  remembered  that 
any  piece  of  timber  measures  more  on 
the  angle  than  on  a  square,  the  won- 
der will  cease.  The  diagonals  we  have 
been  ending  are  taken  off  and  applied 
in  the  same  direction  in  which  they 
are  seen  in  the  body  plan.  The  lines 
are  taken  off  from  the  body  plan  by 
taking  a  thin  batten  and  applying   one 


edge  to  the  diagonal  line  to  be  taken  oft' 
in  the  body  plan,  keeping  one  end  to 
the  middle-line,  and  then  marking  spots 
on  the  batten  at  the  crossing  of  the 
several  frames;  when  the  frames  are 
all  taken  oft'  on  one  line  in  the  same 
body,  they  are  set  off  in  the  hall-breadth 
in  the  same  manner  as  water-lines  are. 
In  the  draught,  they  are  shown  also  in 
the  sheer-plan,  for  which  purpose  they 
are  taken  off  in  the  body  plan  perpen- 
dicularly from  the  base  to  the  crossing 
of  the  frame  and  diagonal,  and  set  up 
in  the  same  manner  in  the  sheer-plan 
on  the  corresponding  frames  upon 
which  they  were  taken  from  the  body 
plan. 

This  method  is  still  practised  in 
Europe,  but  has  long  since  been  re- 
pudiated in  the  ship-yards  of  the  United 
States;  and  there  are  ships  built  that 
when  regulated  on  the  floor  or  on  the 
stocks  exhibit  as  few  discrepancies  as 
those  of  the  Old  World.  We  say  that 
neither  the  expanded  diagonal  in  the 
half-breadth, or  the  horizontal  represen- 
tation in  the  sheer-plan,  are  absolutely 
required  on  the  floor  of  the  loft  to  fair 
the  body  of  a  ship  ;  and  we  have  laid 
down  vessels  without  using  even  diago- 
nals, and  the  vessels  when  raised  ex- 
hibited as  fair  a  frame  as  could  be  de- 
sired. These,  however,  are  exceptions 
to  the  general  rule,  and  will  only  apply 
to   very  sharp    vessels  or  steamboats  ; 


MARINE    AND    NAVAL    ARCHITECTURE 


181 


and  when  such  course  is  adopted,  great 
care  must  betaken  in  the  first  proof 
with  the  water-lines.  The  present 
mode  (and  doubtless  the  very  best)  of 
proving  the  body  by  diagonal  lines,  af- 
ter having  been  first  made  fair,  and 
proved  by  water-lines,  is  to  take  all  the 
settings-off  from  the  body  plan  horizon- 
tally from  the  middle-line  to  the  cross- 
ing of  the  frame  by  the  diagonal,  as 
shown  in  Plate  9;  that  is  to  say — begin 
with  dead-flat,  taking  one  diagonal, 
and  rise  as  the  diagonal  rises,  keeping 
the  batten  horizontal  or  parallel  to  the 
water-line,  and  when  all  the  frames,  or 
all  the  fourth  frames,  are  taken  off  on 
the  batten  from  one  body,  transfer  them 
to  the  half-breadth  in  the  same  man- 
ner that  a  water-line  is  set  off:  the  end- 
ing of  diagonals  when  taken  off  hori- 
zontally differs  from  the  ending  of  those 
taken  off  to  their  full  size.  The  height 
at  which  the  diagonal  crosses  the  side- 
line in  the  body  plan  is  carried  to  the 
sheer-plan,  and  a  spot  marked  on  the 
margin-line  ;  this  being  squared  down 
to  the  half-breadth  on  the  side-line  fur- 
nishes us  with  a  spot  from  which  we 
proceed  in  the  same  manner  as  if  end- 
ing a  water-line,  by  setting  off  the  thick- 
ness of  the  plank  on  the  compasses, 
and  placing  one  leg  of  the  compasses 
on  the  spot  just  made,  and  the  other 
toward  the  end  of  the  ship  at  which 
we  may  be  working  ;  resting  on  the  list 


leg    placed    on    the   side-line,  we    may 
sweep   a   quarter  circle   with  the  first 
leg,  and  on  this  circle  the  diagonal  will 
end.       Under    some    circumstances    it 
may  be  found  necessary  to  seek  another 
proof  to  the  work;  in  such  case  we  have 
only  to  take  off  the  heights  at  which 
the  diagonals  cross  the  frames,  which 
are  taken  from  the  base-line  in  a  ver- 
tical or  perpendicular  direction,  and  set 
off  in  the  sheer-plan  ;   the  endings  are 
also  taken  from  the  body  plan,  and  are 
found  in  the  same   manner,  by  taking 
the   height   from   the  base-line  to    the 
crossing  of  the  side-line  by  the  diago- 
nal.    This  height  applied  to  the  sheer- 
plan,  and  marked  on  the  bearding-line, 
furnishes  all  the  ending  required,  inas- 
much as  the  direction   of  the  line  will 
show  the  height  of  its  final  termination 
on  the  margin-line ;  and  when  the   di- 
agonal lines    are    swept    into  the   ex- 
panded size  in  the  half-breadth,  we  may 
adopt  this  last  method  of  ending  them, 
and  if  there   should  be  any  difference, 
take    the  ending  that   carries   the  line 
farthest    in  ;   that    is    to    say — let    the 
height  be  taken  on  the  side-line  in  the 
body,  and  applied  to  the  bearding-line 
in  the  sheer-plan,  thus  showing  a  spot 
on   the  bearding-line  in  the  sheer-plan 
the  same  height  as  the  crossing  of  the 
side-line    by  the  diagonal    in   the  hod\ 
plan.      Having  swept    in    the   diagonal 
in    the    sheer-plan     a-    in     Plate    9.  the 


182 


MARINE    AND    NAVAL    ARCHITECTURE. 


end  running  fair  across  the  spot  on 
the  hoarding,  and  continuing  to  the 
margin-line,  then  square  down  these 
two  spots  to  the  middle-line  of  the  half- 
breadth;  take  also  the  distance  from 
the  middle-line  of  the  body  plan  to  the 
side-line  in  the  direction  of  the  same 
diagonal  on  which  Ave  are  at  work  ; 
apply  this  distance  on  the  outer  spot, 
or  the  one  squared  down  from  the 
margin-line  ;  take  now  the  thickness 
of  the  plank  in  the  direction  of  the 
same  diagonal  as  shown  in  the  body 
plan  ;  open  the  compasses  to  this  di- 
agonal thickness,  and  place  one  leg  on 
the  spot  squared  down  from  the  mar- 
gin-line, and  the  other  toward  the  end 
of  the  vessel,  (on  the  same  side-line,  or 
the  same  distance  from  the  middle-line,) 
and  resting  on  the  last  leg,  sweep 
a  half  circle  inward,  the  diagonal  will 
end  on  this  circle,  and  cross  the  spot 
squared  down  from  the  bearding-line, 
if  the  work  is  done  properly. 

We  have  now  shown  the  several 
methods  of  ending  the  diagonals,  wheth- 
er swung  off  in  the  diagonal  direction, 
or  taken  off  as  they  now  very  gen- 
erally are,  in  a  horizontal  direction, 
and  ended  as  water-lines,  and  shall 
next  show  how  they  are  ended  on  the 
cross-seam  when  they  come  above  the 
head  of  the  stern-post :  First — if  the 
diagonals  are  to  be  swept  in  as  swung 
off,  they  should  be  continued  in  pencil- 


line  above  the  cross-scam  in  the  body 
plan  as  high  as  the  middle-line  on  the 
draught,  as  shown  by  the  dotted  line  in 
body  plan  of  Plate  9.  Take  the  dis- 
tance square  from  the  middle-line  from 
where  the  diagonal  cuts  the  cross-seam, 
and  set  it  off  in  the  half-breadth  plan 
square  from  the  middle-line  ;  through 
the  spots  thus  obtained,  strike  lines 
square  from  the  middle-line  ;  then  take 
the  distance  on  the  diagonal  in  the  body 
plan  from  the  middle-line  to  the  cross- 
seam,  and  set  off  from  the  middle-line 
in  the  half-breadth  on  its  respective 
line  already  squared  up:  the  spot  thus  '■ 
made  is  the  end  of  the  diagonal.  This 
striking  a  line  square  up  from  the  spot 
pre-supposes  the  cross-seam  to  depart 
from  a  perpendicular  to  the  middle-line, 
either  forward  or  aft.  When  the  di- 
agonals are  swept  in  horizontally,  as 
already  described,  those  ending  on  the 
cross-seam  are  found  by  taking  the  dis-  ' 
tance  from  the  middle-line  in  the  body 
plan  to  the  crossing  of  the  diagonal, 
square  from  the  middle-line,  and  ap- 
plying this  distance  in  the  half-breadth 
on  the  cross-seam  in  the  same  manner  ; 
and  for  the  ending  in  the  sheer-plan  of 
those  lines,  we  have  but  to  refer  to  the 
ending  of  section-lines  on  the  cross- 
seam,  simply  by  taking  the  height  from 
the  body  plan,  at  which  the  diagonals 
intersect  the  cross-seam,  and  setting  up 
the  same  in  the  sheer-plan,  which  will 


MARINE    AND   NAVAL    ARCHITECTURE. 


183 


also  furnish  an  additional  proof  spot  for 
sweeping  in  the  cross-seam  in  the  sheer- 
plan.  Diagonal  lines  taken  off  in  this 
manner  are  called  horizontal  ribbands  ; 
they  are  far  superior  to  the  extended 
mode  tor  all  practical  purposes,  and  we 
are  unable  to  discover  the  reason  why 
they  are  not  universally  adopted  in 
Europe. 

In  laying  down  a  ship  there  are  cer- 
tain points  that  will  serve  as  an  index 
to  test  the  accuracy  of  the  work  ;  these 
may  be  found  in  the  harmony  that  will 
prevail  (if  the  work  is  properly  done) 
between  the  diagonals  and  the  breadths. 
It  is  quite  common  for  the  breadth  and 
diagonal  in  the  body  plan  to  cross  the 
frame  at  the  same  point.     Care  should 
be  taken  to  see  that  they  cross  at  the 
same  point  in  the  half-breadth,  or  ferret 
out  a  reason  why.     We  may  safely  as- 
sume that  the  ship  is  fairly  proved  on 
the  floor,  if  the  diagonals  agree  with 
the  water-lines ;  and  as  it  will   be  ne- 
cessary to  run  in  section-lines  for  some 
distance  from  the  ends,  particularly  the 
stern,   to   obtain  the  bevelling   of  the 
transoms,  we  fairly  conclude  that  there 
has  been  a  sufficiency  of  proofs  to  in- 
sure the  fairness  and  accuracy  of  the 
work  ;   and  having   stricken  in  all  the 
intermediate  frames  across    the    body 
and  sheer-plans,  we    may    regard  the 
work   as    having  been   subjected  to  a 
second  proof  on  the  floor.     The  diago- 


nal line  is  found  to  be  useful,  not  only 
as  a  proof  line,  and  for  the  better  dis- 
tribution of  the  sirmarks,  but  it  aids  in 
the  planking  of  a  ship.  By  following 
the  sirmarks  we  are  enabled  to  make  a 
proper  distribution  of  surface,  and  re- 
duce the  opening  in  due  proportion, 
before  we  may  have  proceeded  far 
enough  to  make  a  division  of  the  same. 
It  must  not,  however,  be  supposed 
that  the  form  of  a  ship  is  consequent 
upon  the  form  or  direction  of  any  par- 
ticular line  or  set  of  lines  ;  on  the  con- 
trary, it  matters  not  what  is  the  direc- 
tion of  the  lines  that  exhibit  the  form  of 
the  vessel:  they  can  run  in  any  direc- 
tion the  builder  may  choose  to  direct. 
Hence  the  reason  why  we  have  shown 
other  directions,  as  in  Fig.  16,  in  order 
that  the  eye  may  not  become  so  com- 
pletely wedded  to  one  form  of  line 
(which  brings  a  particular  shape)  that 
we  cannot  depart  from  it.  We  have 
no  desire  to  break  down  the  rules  and 
usages  universally  recognized  in  this 
seemingly  complicated  art.  It  is  only 
aaainst  their  trammeling  influence  that 
we  raise  our  voice.  It  will  appear 
quite  clear  that  there  is  danger  when 
ship-builders  themselves  tell  us,  that 
their  eye  is  circumscribed  by  a  certain 
shape.  How  important  then  that  the 
young  mechanic  should  be  entirely  free 
from  these  iron  bands  of  habit  !  When 
studying  tin;  laws  of  motion  and  utility, 


1S4 


MARINE    AND    NAVAL    ARCHITECTURE. 


experience  is  vastly  important  we  ad- 
mit, but  there  are  a  thousand  things 
about  a  ship,  from  the  false  keel  to  the 
truck,  and  from  the  end  of  the  flying 
jib-boom  to  that  of  the  spanker-boom, 
that  the  most  experienced  have  never 
been  able  to  give  a  why  or  a  wherefore; 
and  we  deem  the  time  well  spent  by. 
the  young  man  who  will  stop  to  think 
and  inquire  before  he  makes  sail  at 
random,  and  steers  in  the  wake  of  his 
predecessors. 

It  has  been  assumed  by  judicious 
American  writers  upon  the  subject  of 
building  ships,  that  were  the  science  to 
make  no  farther  progress  than  it  has 
already  attained,  it  is  evident  that  it  is 
so  far  perfect  as  to  be  available  for, 
and  capable  of,  being  made  to  keep 
pace  with  the  wants  of  mankind.  We, 
however,  dissent  from  those  elevated 
views,  although  apparently  on  the  eve 
of  a  most  important  era.  It  requires 
but  a  removal  of  the  frowning  influ- 
ence engendered  by  the  indifference 
manifested  by  the  Government  of  the 
United  States  to  the  advancement  of 
commercial  science,  to  convince  the 
world  that  the  science  of  building  ships 
is  yet  in  its  infancy.  Individual  efforts 
to  improve  the  shape  of  vessels  for 
commercial  purposes  can  only  be  sus- 
tained by  national  efforts.  Unlike  other 
improvements,  that  can  be  patented, 
and    the    advantages    secured   to    the 


rightful  owner,  every  improvement  in 
the  form  of  vessels  is  common  property. 
Shape  in  vessels  cannot  be  secured  by 
patent  laws ;  hence  the  propriety  of 
the  fostering  influence  of  Government 
to  sustain  improvements. 

The  mechanic  may  spend  the  flower 
of  his  youth ;  he  may  waste  the  vigor 
of  manhood,  in  maturing  (from  expe- 
rience as  well  as  from  the  laws  of  com- 
mercial science)  the  synthetical  com- 
position of  the  perfect  ship  ;  he  makes 
known  his  improvements  ;  the  world  is 
benefited,  and  he  dies  forgotten,  as  a 
dream.  Hence  we  infer  that  it  ought 
not  to  be  expected  that  the  science  of 
building  this  stupendous  fabric  should 
keep  pace  with  other  improvements  of 
this  improving  age,  without  the  assist- 
ance of  the  fostering  care  of  the  Gov- 
ernment; but  strange  to  tell,  notwith- 
standing the  many  millions  of  dollars 
spent  in  building  Government  vessels, 
Marine  Architecture  is  at  the  present 
time  in  advance  of  Naval  Architecture. 
We  have  been  led  to  offer  the  above 
considerations  before  entering  upon 
the  disquisition  of  a  subject,  for  the  in- 
troduction of  which  we  have  set  apart 
a  portion  of  this  chapter. 

It  has  been  the  object  of  numerous 
men  of  science  (who  have  devoted  the 
whole  or  a  portion  of  their  attention  to 
the  various  problems  embraced  in  the 
theory  of  ships)  to  define,  either  by  the 


MARINE    AND    NAVAL    ARCHITECTURE. 


1S5 


aid  of  mathematical  demonstration,  or 
by  experimental  induction,  the  various 
properties  of*  a  ship,  from  which  we 
may  fairly  conclude  that  few  of  its  ab- 
stract principles  remain  uninvestigated. 
Efforts,  however,  have  not  ceased  to 
bring  something  tangible  from  the  sci- 
ence  of  numbers  that  shall,  to  some 
extent,  set  experience  aside,  by  placing 
it  in  the  back  ground.  An  idea  has 
prevailed  in  the  mechanical  world,  that 
scientific  knowledge  was  reserved  for 
the  comprehension  of  minds  of  more 
than  an  ordinary  calibre.  We  appre- 
hend this  to  be  a  great  mistake  ;  the 
term  science  may  be  applied  to  any 
branch  of  knowledge  that  may  be  made 
the  subject  of  investigation,  with  a 
view  to  discover  its  first  principles,  as 
distinguished  from  art.  A  science  is  a 
body  of  truths,  the  common  principles 
of  which  are  supposed  to  be  known 
and  separated,  so  that  the  individual 
truths,  even  though  some  or  all  may  be 
clear  in  themselves,  have  a  guarantee 
tliat  they  could  have  been  discovered 
and  known,  either  with  certainty,  or 
with  such  probability  as  the  subject 
admits  of,  by  other  means  than  their 
own  evidence.  In  its  most  restricted 
sense,  it  is  but  the  ability  to  give  a  why 
and  a  wherefore  for  our  daily  practice, 
or,  as  lias  been  already  observed,  pro- 
portion, to  effect  the  object  designed ; 
and  we  hesitate  not  to  venture  the  as- 


sertion, that  proportion  is  to  the  scien- 
tific Ship-builder  what  the  fulcrum  is 
to  the  lever,  or  the  axle  to  the  pulley 
— it  is  the  basis  of  all  science  in  me- 
chanism. The  man  of  observation 
has  but  to  look  around  him,  and  he 
will  discover  that  nature's  beauty  con- 
sists in  proportion ;  it  is  universally 
diffused  through  all  her  works,  from 
the  glow-worm  that  lights  his  path,  to 
the  rain-bow  that  spans  the  heavens. 
The  absence  of  this  all-important  quali- 
ty has  wrecked  the  fairest  prospects  of 
many  an  artizan.  This  is  a  shoal  laid 
down  in  no  mechanical  chart;  and  upon 
no  branch  connected  with  the  construc- 
tion of  this  ponderous  fabric,  is  the 
mechanic  more  at  loss. 

It  must  be  admitted  by  all  who  will 
take  the  trouble  to  think,  that  a  ship 
is  actually  stronger  than  another  when, 
upon  a  trial  of  strength,  the  first  would 
break  in  every  part  at  the  same  time, 
while  the  second  would  be  found  much 
stronger  in  some  parts  than  in  others, 
even  though  all  the  parts  of  the  first 
example  were  adapted  or  proportionate 
to  the  weaker  parts  of  the  second  exam- 
ple. This,  to  many,  may  appear  most 
absurd.  There  are  some  even  in  the 
mechanical  world,  who  suppose  that  if 
a  vessel,  or  a  particular  part  of  a  ves- 
sel, looks  heavy,  that  it  must  of  neces- 
sity be  stronger  than  another  having 
less   of  the   large,   heavy  appearance. 


24 


186 


MARINE   AND    NAVAL    ARCHITECTURE. 


This  error  has  proved  fatal  to  thou- 
sands in  the  mechanical  world  ;  but  we 
stop  not  here.  Proportion  is  equally 
as  well  applied  to  the  science  of  num- 
bers as  to  mechanics;  and  it  should  not 
be  forgotten  that  the  science  of  build- 
ing- ships  embraces  the  science  of  num- 
bers or  proportion,  which  in  geometry 
or  arithmetic  is  the  similitude  or  equali- 
ty of  ratios.  There  are  several  de- 
nominations of  proportional  quantities 
in  this  science :  only  one  of  which, 
however,  stands  connected  with  the 
subject  claiming  a  place  in  this  chap- 
ter, viz.,  direct  proportion.  Plate  10 
furnishes  an  exposition  of  the  manner 
of  determining  the  form  of  all  the  lines 
of  a  vessel  below  water.  After  having 
first  settled  upon  the  form  of  the  first 
frame,  or  the  dead-flat  frame,  and  next 
upon  a  diagonal  line  that  will  be  found 
to  show  the  largest  space  between  the 
frames,  as  in  Plate  10.  The  direction 
of  this  line  would,  in  a  majority  of 
cases,  be  found  to  range  from  the  mid- 
dle of  the  bilge  to  the  cross-seam  at  the 
middle-line.  We  may  now  determine 
upon  the  form  of  this  line  in  its  ex- 
tended direction,  after  having  swept  in 
the  dead-flat  frame.  It  will  be  quite 
unnecessary  to  descant  upon  the  pro- 
per form  for  this  frame.  As  there  are 
such  a  variety  of  conflicting  circum- 
stances, that  each  in  its  turn  demand 
our  attention,  the   reader  would,  after 


all  our  expositions,  be  left  to  determine 
its  form  from  his  judgment    or  experi- 
ence ;   and  the   forms  we   shall  furnish 
in    connection   with    a    description    of 
their    appropriate    qualities,    some    of 
which    have    been    already    described, 
will  be  all  that  will  be  required.     Hav- 
ing the  form  of  the  greatest  transverse 
section,  and  the  form  of  the  diagonal  in 
the  direction  we  have  shown,  our  next 
business  is  to  determine  the   form   of 
the  remaining  parts  of  the  immersed 
portion    from    these. 

We  are  aware  that  some  persons 
have  strenuously  contended  that  the 
entire  ship  may  be  formed  by  calcula- 
tions, but  we  are  content  with  blending 
practice  with  theory,  as  a  restrictive 
barrier  against  encroachments.  That 
a  ship  may  be  formed  entirely  from 
calculations,  or  by  the  use  of  figures, 
does  not  admit  of  a  doubt  in  our  own 
minds  ;  but  what  is  to  be  gained  by 
departing  from  what  we  have  proved 
to  be  available,  is  a  question  that  has 
not  been  answered.  We  may  deter- 
mine the  entire  ship's  form  by  theo- 
rems; take  the  parabolic  curve,  and 
we  have  in  it  the  form  of  the  diagonal 
line,  of  which  we  have  spoken  ;  take 
Mr.  Russell's  wave-line,  and  we  have 
the  form  of  the  water-lines  mathema- 
tically determined  ;  and  again,  we  may 
find  an  hundred  ways  of  sweeping  in 
the  dead-flat  frame.    These  modes  have 


MARINE    AND    NAVAL    ARCHITECTURE. 


187 


been  resorted  to  in  the  Old  World  for 
centuries,  and  what  has  been  the  re- 
sult ?  Vessels  built  under  the  old  sys- 
tem in  Europe  are  far  from  being  the 
easiest  vessels  in  their  motions.  It 
cannot  be  denied  that  American  ships, 
(their  principal  dimensions  being-  con- 
sidered,) are  the  easiest  ships  afloat. 
With  an  almost  universal  low  centre 
of  effort,  they  are  the  wonder  and  ad- 
miration of  the  whole  commercial 
world.  It  requires  no  mathematical 
demonstration  to  prove  that  the  mid- 
ship section  should  be  straight  from  the 
keel  outward,  beyond  the  quarter 
breadth,  to  give  stability  to  a  narrow 
ship.  It  requires  no  second  demon- 
stration of  the  same  kind  to  convince 
us  that  the  wall-sided  ship  will  roll  far- 
ther than  the  vertically  round-sided 
ship,  other  things  being  equal  ;  hence 
the  reason  why  we  are  unwilling-  to 
change  our  anchorage,  when  we  know 
we  have  good  holding  bottom  for 
another  that  we  know  less  about,  and 
this  too  merely  for  the  sake  of  change. 
The  system  we  are  about  introducing 
carries  with  it  indelible  proofs  of  its 
utility  and  perfect  adaptation  to  all 
classes  of  vessels,  and  while  it  provides 
for  the  bottom,  it  is  applicable  to  any 
desired  form  above  water.  In  Plate 
10  we  have  taken  the  topsides  of  one 
of  the  packet-ships,  and  it  will  be  seen 
that  they  blend  harmoniously.      Hence 


we  say  that  it  will  adapt  itself  to  any 
form,  not  because  it  is  adapted  to  the 
form  we  have  shown,  but  because  we 
have  made  the  application  to  a  variety 
of  forms,  and  have  found  no  discre- 
pancy. We  say,  then,  that  any  form  of 
diagonal  can  be  successfully  applied  to 
this  system.  Having  the  form  of  the 
dead-flat  frame  in  the  body-plan,  and 
the  diagonal  carried  as  before  stated, 
through  the  centre  of  the  bilge  to  the 
cross-seam,  (the  direction,  however,  is 
not  arbitrary,)  we  may  next  take  the 
half-breadths  from  the  half-breadth 
plan  of  this  diagonal  line,  and  whatever 
distance  they  fall  within  each  other  on 
this  diagonal  in  the  body-plan,  a  spot 
may  be  made  ;  this  diagonal  line  may 
be  taken  swung  oft",  or  taken  horizon- 
tal, but  as  the  first  half-breadth  is  taken, 
so  all  the  remaining  ones  should  be  ; 
that  is  to  say,  if  after  we  have  the  line 
in  the  body-plan  showing  its  direction, 
we  measure  the  half-breadth  of  the 
dead-flat  frame  from  the  point  where 
this  line  terminates,  to  the  middle-line 
horizontally.  We  must  also  set  oft'  in 
the  half-breadth  plan  this  half-breadth, 
as  the  starting  point  for  sweeping  in  the 
diagonal.  It  will  be  necessary  that  we 
should  divide  the  halt- breadth  and 
sheer-plans  into  the  spaces  for  the 
frames,  (as  this  system  contemplates 
the  shape,  and  not  the  stations  of  the 
frames,)  and   having  done   so,  we  next 


18S 


MARINE    AND    NAVAL    ARCHITECTURE. 


lake  off  those  half-breadths  and  apply 
them  in  the  same  manner  as  we  took 
off  the  dead-flat  successively  above  each 
other  in  both  body-plans;  and  although 
the  diagonals  in  both  bodies  end  at  the 
same  point  on  the  middle-line,  and  are 
equi-distant  on  the  dead-flat  frame  from 
the  middle-line,  it  does  not  follow  that 
the  form  of  the  diagonal  in  the  half- 
breadth  plan  is  alike  in  both  bodies. 
We  may  remark  here,  that  if  the  set- 
tings off  on  the  diagonal  are  horizon- 
tal, the  line  in  the  body-plan  need  ex- 
tend no  farther  than  the  last  frame,  or 
the  last  setting  off,  but  if  taken  swung 
off,  it  should  extend  to  the  middle-line. 
It  is  presumed  that  the  openings  on  this 
diagonal  line  in  the  body-plan  are  to  be 
the  largest  that  can  be  found  on  the 
bottom,  and  being  so,  may  be  regarded 
as  unit  or  100.  We  may  now  exercise 
our  judgment  in  arranging  diagonals, 
both  above  and  below  this  line  ;  this, 
however,  is  only  a  temporary  arrange- 
ment, until  we  determine  the  propor- 
tion the  diagonal  bears,  not  that  it  will 
not  apply  equally  well  anywhere,  as 
far  as  the  shape  is  concerned,  but  we 
shall  And  it  much  more  convenient  to 
calculate  ;  for  example,  75  or  SO  per 
cent,  than  81| ;  and  this  is  why  we 
would  so  arrange  the  diagonals  that  an 
even  ratio  may  be  obtained.  In  Plate 
10  we  have  assumed  the  ratios  to  be 
what  they  are  there  shown  to  be  ;   had 


we  wanted  a  different  formed  ship,  we 
could  have  obtained  it  by  altering  the 
ratio  ;  that  is  to  say,  if  we  desired  to 
make  her  sharper  below  the  first  diago- 
nal swept  in,  we  have  but  to  call  the 
diagonal  showing  a  ratio  of  75  parts  to 
80,  and  we  increase  the  spaces  between 
the  frames  at  that  diagonal,  or  cause 
them  to  fall  in  faster;  on  the  other 
hand,  if  we  wanted  to  make  the  ship 
fuller,  we  have  but  to  make  the  75 
parts  pass  current  for  70,  and  we  have 
our  desire ;  the  spaces  between  the 
frames  in  the  body-plan  growing  small- 
er, it  follows  that  the  ship  is  fuller  on 
that  particular  line  ;  but  again,  we  may 
accomplish  the  same  end  by  changing 
the  location  of  the  diagonal,  while  its 
ratio  remained  the  same.  Thus  we  see 
that  a  system  of  proportion  is  at  once 
established — based  upon  the  proper 
formation  of  the  greatest  transverse 
section;  and  if  we  are  so  disposed,  we 
may  carry  the  system  to  the  rail,  in- 
stead of  stopping  at  the  load-line  of 
flotation,  and  perhaps  there  would 
scarce  be  a  discrepancy  found,  in  the 
example  given  in  Plate  10.  The  most 
important  feature  in  this  system,  is  its 
simplicity;  it  is  adapted  to  the  wauls 
of  all,  and  perfectly  comprehensible  to 
the  least  discerning  mind.  We  admit 
that  a  small  share  of  experience  is  re- 
quisite to  determine  the  form,  but  we 
should   be  quite   unwilling  to  set   prac- 


MARINE    AND    NAVAL    ARCHITECTURE, 


189 


tice    aside    altogether,    and    substitute 
theory  in  its  room  ;   but  to  the  opera- 
tive mechanic  this  method  of  modelling 
vessels  will  at  once  commend  itself  as 
being  adapted  to  his  wants.      It   stops 
not  here;  it  is  not  enough  to  say  that  it 
will  give  us  a  form  for  the  ship,  or  other 
vessel,  but   we    may  add,  that  it   will 
regulate  any  form,  without  materially 
altering  the  shape,  unless  the  shape  to 
which  it  is  applied  be  distorted  by  dis- 
proportions ;   it  is  applicable  to  any  di- 
mension, and  tenders  its  aid  as  a  uni- 
versal alkahest  for  many  of  the  ma- 
rine architectural  blunders  for  which 
the  present  age  has  become  notorious. 
In  reviewing  the  many  and  difficult 
questions  involved  in  an  effort  to  eluci- 
date   the    philosophical    principles    in- 
volved with  the  building  of  ships,  we 
are  forcibly  led  to  exclaim   with  a  dis- 
tinguished writer  on  Naval  Architec- 
ture — "  To  whom  are  we  to  look  for 
improvements   in    the   construction   of 
ships?     Is  it    to   the    men    who   may 
bring  forward  some  geometrical  or  me- 
chanical  series   of  curved  lines   for   a 
ship's  body,  deduced  from  one  or  more 
curves  ?    for  this  has  been  many  times 
done,   and   may   be   performed   by  the 
mere  dabbler  in   the  art,  or  to  those 
who,   regardless  of  any  rules,  build 
ships  by   what  they  call  the  eye  !    for 
there  are   many  of  these  ;    and  when 
either   are  asked  for  reasons  for  any 


particular  construction,  they  assume 
mysticism,  and  would  appear  wise  by 
saying  nothing.  Certainly  from  no 
such  men  are  we  to  hope  for  improve- 
ments in  a  science  pregnant  with  diffi- 
culties, to  surmount  which  seems  to 
exceed  the  force  of  the  human  under- 
standing." 

But  let  us  look  for  the  advancement 
of  Naval  Architecture  to  those  who 
unite  the  theory  with  the  practice — 
who  are  patient  observers  of  the  physi- 
cal facts  which  experience  brings  to 
their  view,  and  have  sufficient  science 
to  account  for  these,  either  by  laws, 
long  established,  or  if  not,  to  endeavor 
to  discover  new  ones.  For  what  is 
theory  in  its  legitimate  sense  but  a  law 
or  system  of  laws,  established  and  con- 
firmed by  a  series  of  well-conducted  ex- 
periments? We  may,  perhaps,  be  al- 
lowed to  add,  that  theory  and  practice 
combined  constitute  Art,  or  with 
Shakspeare  exclaim,  that  "  Art  itself 
is  Nature,"  and  qualify  the  former  in 
the  language  of  Pope — "  Art  is  but 
Nature  better  understood." 

In  our  expositions  of  the  system  we 
have  introduced  in  this  chapter,  it  will 
be  understood  that  the  diagonals  (or 
angular  lines)  have  no  connection  with 
the  middle  line — the  line  running 
through  the  bilge  which  we  have 
valued  as  1,  or  unit,  may  take  its  de- 
parture from  the  side-line  in  the  body- 


190 


MARINE    AND    NAVAL    ARCHITECTURE 


plan,  because  we  cannot  determine  the 

form  of  the  entire  line  in  its  rotundity 
without  the  connection,  but  after  this 
line  is  determined  in  its  relative  form, 
the  connection  may  cease;  by  this 
method  the  labors  of  the  loft  may  be 
materially  abridged,  and  the  work  per- 
formed with  an  equal  amount  of  ex- 
actness. 

In  the  application  of  this  system  to 
the  topsides  of  the  vessel,  we  may  adopt 
the  straight,  or  sheer-line,  and  the  pro- 
portions will  apply  equally  well.  We 
may,  however,  find  it  necessary  to  de- 
part from  those  proportions  above 
water,  particularly  on  the  anterior  part, 
or  on  the  flare  of  thebow,  which  beauti- 
fies and  adorns  this  part  of  the  structure. 
When  this  is  the  case,  it  will  only  be 
necessary  to  lake  the  lower  sheer-line 
for  unity,  and  proportion  the  sheer-lines 
above  in  their  proper  ratios.  In  ap- 
plying this  method  to  the  loft,  we  have 
but  to  regulate  unity  in  the  half-breadth 
as  taken  from  the  draft,  and  transfer- 
ring it  to  unity  represented  in  the  angu- 
lar line  in  the  body-plan.  After  hav- 
ing swept  in  the  dead-flat  frame,  we 
shall  be  able  to  sweep  in  every  frame 
with  precision.  Supposing  any  two 
frames  to  be  a  given  distance  apart  on 
the  line  marked  100,  and  we  require 
the  distance  on  the  next  line  above  or 
below  the  line  for  example  marked  75  ; 
and   assuming   the   space    on    the   line 


marked  100  to  be  10  inches,  we  now 
want  to  know  what  it  should  be  on  the 
line  marked  75.  We  obtain  it  in  the 
following  manner — 

inches        Inchon       inches       inches 

IflOO:    10  :  :  75:  ?.\  or  75x  I  0-HtOO=7j 

The  openings  may  be  thus  regulated 
(it  matters  not  how  small  or  how  large 
they  may  be)  with  precision.  This 
system  of  proportions  is  not  however 
confined  exclusively  to  this  arrange- 
ment. In  all  questions  assuming  an 
algebraic  form,  it  is  absolutely  neces- 
sary that  we  should  assume  propor- 
tions upon  which  we  can  base  our 
calculations,  and  from  which  we  may 
arrive  at  inevitable  results.  If  we  as- 
sume the  dead-flat  frame  to  be  of  such 
form  as  we  desire,  and  the  load  water- 
line  to  be  formed  in  accordance  with 
our  judgment,  the  remaining  parts  be- 
low are  readily  determined,  and  the 
spots  tints  obtained  will  prove  the  sur- 
passing accuracy  of  numbers  for  me- 
chanical operations  (when  properly 
handled.)  If  we  assume  the  body-plan 
of  a  ship  to  be  divided  between  the  base 
and  load-line  into  six  equal  or  unequal 
parts,  as  we  please,  the  lines  being  hori- 
zontal and  parallel  to  each  other,  and 
the  load-line  shown  in  three  plans, 
viz.,  the  sheer,  half-breadth,  and  body- 
plan  ;  in  the  former  and  the  latter  it  .will 
show  but  a  straight  line,  while  in  the 
half-breadth  plan  it  exhibits  the  form 
in  its   rotundity.      The  load-line  being 


PL.  10 


MARINE    AND    NAVAL    ARCHITECTURE. 


191 


the  widest  part  of  the  bottom,  we  set 
against  it  1000  or  unit,  which  is  1. 
Suppose,  as  is  the  case,  the  half- 
breadth  of  ®  frame  to  be  13  feet  on  the 
load-line,  12.S9  on  the  fifth  water-line, 
12.75  on  the  fourth  water-line,  12.46 
on  the  third  water-line,  11.58  on  the 
second  water-line,  and  9.83  on  the  first 
water-line ;  now  it  will  appear  quite 
manifest,  that  those  several  breadths 
are  units,  or  whole  parts,  this  being  the 
widest  frame  in  the  ship,  and  as  the 
lines  below  grow  narrower  on  all  the 
frames,  or  have  less  breadth  successive- 
ly as  we  descend,  it  follows  that  the 
lower  half-breadths  of  the  dead-flat 
frame  are  of  necessity  fractional  parts 
of  the  unit.  We  will  now  give  the  half- 
breadths  of  the  dead-flat  frame,  on 
the  several  water-lines,  first  in  feet  and 
inches,  then  in  feet  and  decimal  parts, 
and  third  in  decimal  parts  of  the  unit. 
First — the  load  or  sixth  water-line 
equals  13  feet ;  fifth  water-line,  12  feet 
10  and  three  quarter  inches  ;  the  fourth 
water-line,  12  feet  9  inches  ;  the  third 
water-line,  12  feet  5  and  a  half  inches; 
the  second  water-line,  11  feet  7  inches  ; 
the  first  water-line,  9  feet  10  inches. 
It  will  be  observed  that  there  being  no 
inches  appended  to  the  half-breadth  of 
the  dead-flat  on  the  load-line,  the  ex- 
pression is  alike,  in  both  eases  13  feet ; 
the  half-breadth  on  the  fifth  water-line 
is    12.S9   feet;    on    the    fourth,   12.75 


feet;  on  the  third,  12.46  feet;  on  the 
second,  11.58  feet  ;  and  on  the  first, 
9. S3  feet.  These  half-breadths  are  re- 
spectively represented  as  follows — the 
sixth  or  load-line,  unit  1  or  1000,  which 
is  the  same  thing  ;  the  fifth  is  to  the 
sixth  as  .993  is  to  1000.  Hence  it  fol- 
lows that  the  half-breadth  of  dead-flat 
on  the  fifth  water-line  is  nine  hundred 
and  ninety-three  thousandths  of  that  of 
the  load-line,  as  is  recognized  by  the 
above  expression.  So  also  with  the 
fourth  water-line :  that  is  to  the  load- 
line  as  nine  hundred  and  eightv-one  is 
to  one  thousand,  and  also  expressed  as 
above  .981.  The  third  water-line  half- 
breadth  is  likewise  expressed  in  the 
same  manner — twelve  feet  five  inches 
and  a  half  equals  .958  of  thirteen  feet. 
The  second  water-line  half-breadth  be- 
ing eleven  feet  seven  inches,  is  equiva- 
lent to  .891  thousandths  of  thirteen 
feet,  or  the  half-breadth  of  the  sixth 
water-line.  In  like  manner  the  first 
water-line  bears  a  ratio  of  .756  thou- 
sandths of  the  load-line,  or  of  thirteen 
feet. 

We  have  thus  given  the  ratios  of  the 
greatest  transverse  section,  from  which 
it  follows  that  the  half-breadths  of  every 
frame  (according  to  this  system)  bears 
the  same  ratio  to  its  own  half-breadth 
on  the  load-line,  that  the  dead-flat  does. 
We  shall  denominate  the  load  of  flo- 
tation  unit,  or   1000,  on  every   frame: 


192 


MARINE    AND    NAVAL    ARCHITECTURE 


and  assuming  that  the  greatest  trans- 
verse section  and  the  load-line  are 
about  right,  we  have  the  intermediate 
immersed  space  to  furnish  by  calcula- 
tion. Having  determined  the  breadth 
at  the  several  water-lines  on  the  dead- 
flat  frame,  it  is  necessary  that  we  pro- 
ceed to  obtain  the  breadths  on  the  sev- 
eral frames,  or  fourth  frames,  at  the 
load-line  of  flotation ;  and  having-  set 
down  their  breadth  in  feet  and  inches, 
or  feet  and  fractional  parts,  which  half- 
breadths,  it  will  be  remembered,  are 
each  in  themselves  a  unit,  because  the 
several  frames  are  wider,  or  have  their 
greatest  breadth  at  the  load-line  of  flo- 
tation, we  have  the  half-breadth  of  the 
dead-flat,  which  is  13  feet.  And  we 
will  assume  the  half-breadth  of  any 
frame  (say  frame  20)  to  be  8  feet  on 
the  load-line  ;  we  now  want  to  find  the 
half-breadth  of  frame  20  on  the  five 
water-lines  below  the  load-line ;  we 
have  already  found  that  the  fifth  water- 
line  was  .993  of  the  sixth  at  dead-flat, 
we  then  have  the  following  formula  to 
determine  the  half-breadth  of  frame  20 
on  the  fifth  water-line — As  1000 :  13 
feet  : :  .993  :  12  feet  10  inches  three 
quarters  and  nearly  one  sixteenth,  or  if 
the  extreme  breadth  on  the  dead-flat 
is  thirteen  feet,  what  is  the  half-breadth 
of  frame  20  on  the  fifth  water-line  1 
Supposing  that  of  frame  20  to  be  8 
feet  on  the  load,   or  sixth  water-line, 


we  shall  be  able  to  determine  the  en- 
tire shape  of  the  bottom  in  the  manner 
already  shown:  and  to  illustrate  the 
principle  more  fully,  we  will  take 
another  example.  It  will  be  remem- 
bered that  when  we  supposed  the  half- 
breadth  of  frame  20,  we  did  so  because 
we  had  not  given  the  proportions,  or 
the  actual  half-breadths  of  the  load-line 
on  every  frame;  and  we  had  not  given 
those  half-breadths  for  the  obvious  rea- 
son that  it  would  tend  to  confuse 
rather  than  instruct,  to  impart  a  second 
series  of  proportions  before  the  first  was 
fairly  digested,  or  properly  understood. 
Hence  the  reason  of  adopting  the  pres- 
ent course  ;  but  this  cannot  alter  the 
results;  it  makes  no  difference  whether 
the  half-breadth  of  frame  20  is  8  feet, 
or  any  other  number  of  feet,  the  pro- 
portion will  hold  good  with  any  num- 
ber. 

We  will  now  take  an  example  on  the 
fourth  water-line  with  another  frame. 
Supposing  frame  12  to  have  9  feet  4 
inches  for  its  half-breadth  at  load-line, 
required  the  half-breadth  of  the  same 
frame  on  the  fourth  water-line,  we  then 
have  but  to  reduce  the  9  feet  4  to 
inches,  also  the  13  feet,  the  half-breadth 
of  0  frame,  when  we  have  the  formula 
in  the  following  shape — 

inches  incite* 

1000:   112  :  :   .981  :   l&Si, 

or  9  feet  and  I  of  an  inch.  In  this  lat- 
ter example,  we  have  found  that  the 


MARINE  AND  NAVAL  ARCHITECTURE. 


193 


first  term  remains  the  same  as  in  the 
first  example,  while  the  second  has  al- 
tered ;  but  it  must  not  be  forgotten  that 
the  breadth  on  load-line  is  a  unit  on 
every  frame,  and  this  being  placed  as 
the  first  term,  must  not  be  otherwise 
represented.  The  second  term  being 
the  actual  breadth  expressed  in  feet 
and  inches,  or  in  feet  and  decimal  parts, 
it  follows  that  the  third  term  will  be 
the  ratio  the  half-breadth  of  dead-flat 
frame  on  load-line  bears  to  the  same 
frame  on  the  water-line,  upon  which 
the  breadth  is  to  be  determined.  The 
last  example  can  also  be  expressed  as 
follows : 


feet 

9.83  : 


: 


9S 


1000  :  9.33  :  :   .9S1 

the  result  is  the   same. 

We  will  follow  those  examples 
hrough  the  first  series.  The  half- 
breadth  of  another  frame  on  the  third 
water-line  will  in  like  manner  be  de- 
termined. We  will  assume  its  half- 
breadth  to  be  8  feet  7  inches  and  one- 
eighth  at  load-line,  and  we  require  the 
half-breadth  at  the  third  water-line  ; 
we  will  for  convenience  call  the  frame 
14  ;  the  half-breadth  is  expressed  thus  : 
8.59 — as  we  shall  find  by  referring  to 
page  3 — we  then  have, 


feet 

S.59 


feet 

S.12 


1000  :  S.59  :  :  .95S 

which  last  or  third  term  is  the  ratio 
the  dead-flat  frame  on  third  water- 
line  bears  to  the  same  frame  on  the 
load-line;    hence    it    follows    that    the 


proportion  gives  £&  nearly,  or  8  feet  1 
inch  and  a  half  nearly.  The  second 
water-line  on  the  dead-flat  frame  is  to 
breadth  on  load-line  as  .S91  is  to  one 
thousand;  and  if  we  assume  the  half- 
breadth  of  any  frame  on  that  line  to  be 
any  breadth  we  please,  say  7  feet  9, 
and  we  shall  again  find  the  same 
proportionate  results  :  1000  :  7.7-5  : : 
.891:  6%,  the  result  is  6  feet  10 
inches  and  nearly  seven-eighths.  The 
first  water-line  being  .756,  furnishes  all 
the  spots  that  will  be  necessary  to 
complete  the  first  series  of  proportions  ; 
and  it  may  be  well  here  to  remark,  that 
the  calculations,  if  made  with  care,  will 
be  found  to  furnish  the  spots  much 
more  exact  than  any  man  can  deter- 
mine them  by  the  ordinary  mode  of 
taking  off  tables  and  fairing  on  the 
floor.  No  man,  we  care  not  how  care- 
ful he  may  be,  can  even  approximate 
the  accuracy  that  this  system  furnishes, 
and  we  speak  on  this  wise  in  reference 
to  all  the  calculation  pertaining  to  a 
ship.  There  are,  however,  a  variety 
of  ways  to  determine  the  body  of  a  ship, 
as  we  have  already  shown  ;  and  per- 
haps it  would  not  be  out  of  place  to  de- 
lineate other  methods.  Before  doing 
so,  it  may  also  be  necessary  to  add,  that 
those  several  modes  are  applicable  to 
the  draft  more  particularly,  and  could 
not  be  applied  directly  to  the  ordinary 
water-line   model,  unless    the   lines   of 


25 


194 


MARINE    AND    NAVAL    ARCHITECTURE. 


the  bottom  were  first  obtained  and  ap- 
plied to  the  model,  for  the  purpose  of 
projecting  the  topsides,  which  method 
may  be  worthy  of  consideration,  for 
two  reasons.  First,  inasmuch  as  it  is 
very  generally  conceded  that  no  man's 
eye  can  penetrate  the  mysterious  laby- 
rinths of  nature,  without  assistance 
procured  by  a  knowledge  of  her  laws, 
as  may  be  inferred  from  what  has  been 
already  shown,  that  the  man  who  mo- 
dels a  vessel  without  this  knowledge, 
won  hi  do  well  to  take  the  draft  as  a 
chart,  and  carry  out  some  one  of  the 
systems  that  we  have  and  will  exhibit  ; 
and  having  familiarized  his  eye  with 
shape  on  the  plane,  then  make  the  ap- 
plication in  its  rotundity  on  the  model, 
carrying  up  the  topsides  to  suit  his 
taste,  or  the  peculiarities  belonging  to 
the  business  in  which  she  may  be  en- 
gaged. The  second  reason  is  found  in 
the  fact,  that  the  diagonal  line  is  not 
shown  on  the  water-line  model,  al- 
though it  approximates  nearer  to  the 
actual  direction  of  the  molecules  of  the 
fluid,  when  propulsion  is  applied  for 
overcoming  inertia  ;  and  if  the  model 
were  made  in  a  manner  we  have  de- 
scribed in  Fig.  16,  showing  the  water- 
line  and  the  diagonal,  it  would  then  be 
almost  impossible  to  make  the  applica- 
tion on  the  model  direct ;  to  say  the 
least,  it  would  be  attended  with  many 
difficulties  ;    whereas   many    who    are 


not  familiar  with  the  draft,  would 
find  that  time  could  be  saved  in  making 
ihemselves  familiar  with  shape  on  the 
plane.  Indeed  we  may  not  be  confined 
to  the  manner  of  determining  the  pro- 
portions from  the  body-plan,  only  in 
the  manner  we  have  shown  from  the 
diagonals.  We  may  divide  the  body 
in  the  usual  manner,  at  regular  inter- 
vals, by  diagonal  lines  ;  not,  however, 
by  paying  direct  reference  to  the 
length  of  the  timbers,  as  is  the  case  on 
the  floor  of  the  mould-loft,  but  by  ar- 
ranging  the  lines  in  such  a  manner  as 
equalize,  or  nearly  so,  the  spaces  above 
the  first  diagonal,  both  on  the  middle- 
line  and  on  the  dead-flat  frame.  We 
may  then,  in  a  manner  we  have  before 
shown,  sweep  in  the  dead-flat  frame ; 
and  the  diagonal  running  through  the 
bilge  (which,  as  also  shown,  represents 
unit)  and  proportion,  those  above  and 
below  finding  the  ratio  each  bears  to  the 
first,  and  marking  them  respectively 
according  to  their  value,  (those  who 
are  at  all  familiar  with  per-centagc, 
must  readily  understand  it  ;)  but  it 
does  not  follow  that  the  line  we  have 
denominated  unk  or  100,  should  be 
actually  the  longest.  Assuming  the  one 
above  were  10  per  cent,  longer,  it 
would  be  only  necessary  to  mark  the 
line  110,  and  we  have  the  ratio;  awd 
having  this,  we  may  sweep  in  any  di- 
agonal we  please  ;  the  ratio  must  regu- 


MARINE    AND    NAVAL    ARCHITECTURE. 


195 


late  the  shape  :  after  we  have  the  frame 
and  the  longitudinal  line,  we  shall  be 
able  to  obtain  a  fair  and  a  proportioned 
bottom.  In  this  manner  we  may  also 
practice  drawing  with  great  advantage, 
and  we  shall  be  able  to  advance  beyond 
our  former  conception.  It  must  not, 
however,  be  supposed  that  the  draft 
alone  will  furnish  us  with  a  correct 
idea  of  shape  in  its  rotundity ;  this 
would  be  requiring  too  much:  but 
with  the  draft  and  model  united,  we 
may  have  all  that  we  require.  With 
the  model  alone,  we  are  dependent 
upon  the  eye,  and  must  of  necessity  be 
thus  dependent,  unless  we  draw  the 
draft,  and  make  moulds  from  it  that 
can  be  applied  in  the  manner  and  at 
the  place  at  which  they  were  made. 
This  would  seem  to  be  the  most  indi- 
rect manner  of  accomplishing  our  pur- 
pose. It  would  be  more  readily  ac- 
complished by  carrying  out  the  pro- 
portions on  the  draft,  and  then  taking 
off  the  water-lines,  as  shown,  or  spaced 
on  the  model,  and  from  these  lines  make 
the  model ;  or  perhaps  we  should  be 
more  definite  by  describing  the  process 
differently.  Assuming  the  body-plan 
to  be  already  swept  in  by  the  diagonal 
lines,  (it  matters  not  for  our  present  pur- 
pose whether  they  are  swept  in  the 
half-breadth,)  we  may  now  divide  the 
body-plan  into  sections  parallel  to  the 
base-line,    as  high   a?  the  load-line   of 


flotation  ;  and  on  those. assumed  water- 
lines  take  the  half-breadths,  the  same 
as  we  would  were  we  laying  down  a 
water-line  model,  or  laying  down  the 
water-lines,  which  in  fact  we  would  be. 
In  this  operation  it  would  be  necessary 
to  draw  the  sheer-plan  on  the  draft, 
else  the  ending  of  the  lines  could  not  be 
obtained.  Hence  it  would  be  neces- 
sary to  apply  the  draft  to  the  model 
in  this  particular  also,  or  we  could  not 
accomplish  our  purpose ;  and  having 
carried  our  model  as  high  as  the  load- 
line  in  strict  conformity  with  the 
draft,  we  could  finish  the  part  above 
water  in  unison  with  the  dictates  of  our 
experience.  It  might  be  found  neces- 
sary, in  order  to  make  the  application 
in  the  latter  case,  to  transfer  the  set- 
tings-off to  the  half-breadth  plan  also. 
In  the  mode  of  proportions  by  water- 
lines  we  may  determine  even  more  than 
the  actual  formation  of  lines ;  these 
proportions  will  furnish  the  actual  dis- 
placement of  the  ship  at  any  line  of  flo- 
tation, after  having  first  determined  the 
actual  area  and  capacity  of  one  sec- 
tion. To  illustrate  this  wc  will  as- 
sume the  water-lines  to  be  two  feet 
apart,  and  that  a  temporary  line  be 
drawn  longitudinally  parallel  to  load- 
line  in  the  sheer-plan,  or  transversely 
parallel  to  load-line  in  the  body-plan. 
one  foot  down,  and  half  way  distant  to 
the  water-line  below  ;   let  the  same  be 


19G 


MARINE    AND    NAVAL    ARCHITECTURE. 


done  with  each  section,  so  that  the 
water-lines  in  the  body-plan  have  be- 
tween them  a  temporary  water-line 
equi-distant  from  each.  We  will  now 
assume  the  area  of  the  upper  line  thus 
temporarily  drawn  to  be  110  square 
feet  ;  this  multiplied  by  2  furnishes  the 
solid  contents  of  the  half-section,  or  of 
the  space  contained  in  the  first  two  feet 
below  the  load-line.  The  ratio  of  the 
second  section  may  be  75  parts  of  the 
first ;  we  then  have  a  formula  like  the 
following — If  100  parts  give  220  cubic 
feet,  what  will  75  parts  give  ?  The 
result  furnishes  165  cubic  feet.  We 
may  pursue  the  same  course  with  those 
below,  by  first  converting  the  area  into 
cubic  feet,  and  then  by  the  rule  of  di- 
rect proportion  we  may  find  the  solid 
contents  ;  and  this  rule  will  be  found 
to  approximate  the  former  system  of 
proportion  by  diagonal  lines,  if  we  will 
but  mark  as  before  the  temporary 
water-lines  and  find  the  proportion 
one  area  bears  to  the  other.  In  this 
case  it  is  but  an  approximation  near 
enough,  however,  for  very  many  pur- 
poses for  which  an  approximation  only 
might  be  required.  In  determining  the 
body  or  the  capacity  of  a  vessel  by  this 
method  of  proportions,  it  is  important 
that  the  question  should  be  stated  pro- 
perly, else  we  may  be  subjected  to  very 
great  errors.  Although  those  problems 
are  but  simple  sums  in  the  rule  of  three. 


with  which  every  school-hoy  may  be 
familiar, yet  many  may  not  readily  know 
how  to  test  the  truth  of  the  statement, 
or  be  able  to  tell  positively  when  the 
sum  is  properly  stated. 

It  is  a  property  of  proportional  num- 
bers derived  directly  from  the  defini- 
tion, that  the  product  of  the  first  and 
fourth  terms  is  equal  to  the  product  of 
the  second  and  third.  Hence  it  fol- 
lows that  when  three  terms  of  a  pro- 
portion are  given,  the  fourth  can  be 
found.  This  is  the  basis  of  all  ques- 
tions in  the  rule  of  three.  The  fore- 
going remarks  apply  exclusively  to 
geometrical  proportion,  or  when  the 
proportion  consistsin  the  equality  of 
ratios. 

The  method  of  proportioning  by 
water-lines  is  somewhat  objectionable, 
for  two  reasons — First,  it  furnishes 
continuation  of  the  bilge  to  the  ex- 
tremities,  in  due  proportion,  it  is  true, 
which  may  seem  to  be  a  plausible 
theory  to  many,  yet  it  has  objection- 
able features  that  will  be  rendered  quite 
apparent  to  the  discerning  mind  upon 
due  reflection.  The  bilge,  however 
necessary  at  the  middle  of  the  ship  to 
sustain  the  leverage  of  the  masts  and 
sails  in  propelling  the  ship  onward,  or 
to  maintain  practical  stability  when 
without  cargo  and  in  a  state  of  rest, 
must  be  regarded  as  detrimental  to 
speed,  when  viewed  as  a  restorative  oi 


MARINE    AND    NAVAL    ARCHITECTURE. 


197 


the  posterior  part  of  a  ship.  The  sud- 
den and  irregular  change  of  course 
the  fluid  takes  in  its  passage  aft  cre- 
ates a  re-action,  that  serves  as  a  regu- 
lating medium ;  the  consequence  is, 
that  a  portion  of  the  fluid  is  constantly 
performing  the  office  of  false  stern,  and 
serves  as  a  regulator  or  conductor  to 
convey  the  contiguous  columns  to  their 
wonted  equilibrium.  This  property 
does  not  contribute  to  increase  the 
disturbance  on  the  bow,  but  does  very 
materially  increase  the  resistance  on 
the  after  end  of  a  ship.  The  second 
reason  that  may  be  assigned  for  repu- 
diating the  proportional  water-line  is 
its  tendency  to  diminish  the  practical 
stability.  The  thinking-man  has  but 
to  reflect  that  the  greater  the  buoyancy 
near  or  at  the  extremities  of  the  ship, 
the  less  stable  the  ship.  Buoyancy 
located  here  to  any  considerable  ex- 
tent has  a  very  deleterious  effect  on 
the  stability  of  vessels,  even  when  the 
vessel  is  light,  or  without  cargo.  Not 
so  with  a  distribution  of  the  buoyancy 
at  the  bilge  near  the  centre ;  when 
light,  she  covers  a  broad  surface,  which 
sustains  her  in  an  upright  position,  but 
when  buoyancy  is  concentrated  at  the 
end  below  in  an  undue  proportion, 
the  vessel  must  of  necessity  careen  or 
incline  easily  when  light. 

AVe   have   already  shown  the  effect 
of  having    a    short  floor   transversely, 


and  this  quality  has  the  same  effect 
upon  the  practical  stability  of  vessels 
that  a  short  floor  transversely  would 
have.  Proportions  by  water-lines, 
however,  would  equalize  the  weather 
and  lee-lines  of  flotation,  and  furnish  a 
very  burdensome  vessel.  It  must  be 
remembered  that  each  water-line  and 
frame  would  bear  an  impress  of  those 
from  which  the  calculation  is  made. 
This  is  not  the  case  with  ratios  by  di- 
agonals;  we  may  obtain  what  shape 
we  desire  through  this  channel,  and 
without  exceptions  we  are  not  tram- 
meled when  we  start  right.  If  we  want 
a  fast  or  full  vessel,  we  can  obtain  suita- 
ble shape  for  either,  and  there  appears 
to  be  but  a  single  objection  to  tin;  in- 
troduction of  this  system  of  modelling 
vessels,  (apart  from  the  controlling  in- 
fluence of  prejudice  ;)  this  objection  is 
found  in  the  fact  that  we  all  want  to 
see  the  end  at  the  beginning,  or  to  have 
the  whole  shape  before  us  from  the 
commencement  of  our  labors.  This 
wish  is  gratified  in  the  use  of  the 
model,  and  cannot  be  in  the  use  of  the 
draft,  notwithstanding  they  are.  or  may 
be  used  in  connection  with  each  other; 
but  this  is  not  all,  there  are  some  who 
build  vessels,  and  even  some  who  build 
ships,  and  are  styled  ship-builders,  who 
cannot  draw  a  draft.  Hence  any  sys- 
tem, however  feasible,  that  requires  the 
use    of    the   pen,  will    be    repudiated. 


19S 


MARTNE   AND    NAVAL    ARCHITECTURE. 


There  are  sonic  problems  connected 
with  building  ships  upon  scientific  prin- 
ciples, that  cannot  be  determined  apart 
from  the  draft ;  and  again,  on  the  other 
hand  there  are  others  that  require  the 
model  for  their  solution,  as  we  have 
partially  shown,  and  unless  a  unison 
takes  place,  the  progress  of  this  science 
must  of  necessity  be  slow.  Experi- 
ence in  this  particular  enables  us  to 
speak  confidently,  knowing  as  we  do 
that  the  discovery  of  this  system  of  ra- 
tios was  consequent  upon  the  use  of  the 
draft  ;  we  practised  and  taught — First, 
proportions  by  water-lines  as  connected 
by  the  ratios  from  the  middle-line,  and 
subsequently  discovered  that  diagonals 
might  be  used  with  still  greater  success  ; 
but  to  those  who  will  not  depart  from 
their  dependence  upon  the  eye,  we  say 
the  model  has  no  equal  in  delineating 
shape  in  its  rotundity.  But  there  are 
still  other  modes  it  is  said  for  determin- 
ing the  proper  plan  for  vessels  of  all 
descriptions,  the  most  prominent  of 
which  we  shall  notice. 

Plate  11  describes  the  path  of  the 
planet  we  inhabit  in  its  trackless  evo- 
lutions around  the  sun.  The  path  as 
thus  delineated  is  assumed  by  more 
than  one  theorist  to  be  the  form,  and 
the  only  form,  that  will  successfully 
compete  with  all  others  in  attaining  a 
high  degree  of  speed.  It  will  not  be 
necessary   to   reiterate  what  we  have 


already  stated  in  relation  to  resistance  ; 
it  would  seem,  however,  that  very  many 
of  those  who  are  so  fond  of  spinning 
fine  theories,  know  somewhat  less  than 
they  should  about  the  element  they 
would  teach  the  world  to  navigate. 
That  inertia  forms  a  great  bulk  of  the 
actual  resistance,  no  one  will  deny  ; 
but  what  analogy  exists  between  the 
resistance  encountered  by  a  body  pro- 
pelled through  air,  and  the  same  body 
partially  immersed  in  water,  and  wholly 
sustained  by  its  buoyant  and  non-elas- 
tic power?  We  ask  this  question  in 
all  candor,  believing  that  those  persons 
who  would  embark  in  an  expedition 
for  the  attainment  of  high  speed,  either 
in  steam  or  sailing  vessels,  would  do 
well  to  look  to  this  distinction  in  the 
circumstances  of  the  two  bodies  thus 
differently  supported — the  one  by  an 
elastic,  the  other  by  a  non-elastic  fluid. 
Again,  water  is  composed  of  round 
molecules,  to  perform  the  office  of  roll- 
ers, which  are  set  in  motion  on  the  very 
smallest  application  of  power,  and  the 
vessel  moves  in  the  direction  that  pow- 
er is  applied.  We  say  that  the  cir- 
cumstances are  so  entirely  different  be- 
tween two  bodies — the  one  submerged 
in  air,  the  other  partly  submerged  in 
both  air  and  water,  that  nothing  tan- 
gible can  be  drawn  from  the  earth's 
path  that  will  furnish  a  shape  for  the 
posterior  part  of  the  vessel  intended  to 


MARINE    AND    NAVAL    ARCHITECTURE. 


199 


navigate  the  ocean  ;  the  aerial  naviga- 
tor may,  but  the  marine  navigator 
cannot :  not  because  we  have  said  so, 
but  because  experience  has  demonstra- 
ted the  truth  of  what  we  have  said. 
The  inertia  which  forms  the  great  bulk 
of  the  resistance  to  be  overcome  would 
forever  lock  every  vessel  to  its  native 
shore,  were  it  not  for  this  essential 
difference  that  exists  between  the  two 
elements,  air  and  water.  The  mole- 
cules of  water  are  like  myriads  of  me- 
tallic balls,  polished  and  frictionless. 
The  number  applied  is  in  exact  pro- 
portion to  the  weight  to  be  sustained ; 
and  as  there  must  of  necessity  be  clash- 
ing where  so  many  rollers  are  set  in 
motion  at  the  same  time,  (unless  the 
shape  be  a  perfect  one,)  we  may  safely 
conclude  this  clashing  to  be  friction,  in 
connection  with  the  irregularities  in 
the  surface  of  the  vessel,  and  the  fibres 
that  protrude  from  timber  of  any  and 
every  kind,  which  also  materially  im- 
pede the  progress  of  vessels.  By  the 
clashing  of  the  molecules  we  mean  the 
many  different  directions  they  are  re- 
quired to  move,  consequent  upon  the 
deformities  in  shape.  But  there  is  one 
fact  above  all  others  which  theorists 
seem  to  lose  sight  of  when  marking  out 
a  course  for  practical  men.  They  en- 
tirely forget  that  the  pressure  is  at 
right  angles,  and  consequently  the  di- 
rection  of   the   molecule   must   be  tin; 


same.  Notwithstanding  they  readily 
acknowledge  this  truth,  we  see  them 
delineating  the  shape  by  diagrams  of 
the  proper  form  for  the  parallels  to  the 
line  of  flotation.  Practical  knowledge 
has  determined  one  point  in  relation  to 
the  proper  formation  of  vessels  for 
speed,  to  which  theory  must  yield  ;  it 
is,  that  the  current  formed  by  the  mov- 
ing vessel  should  be  as  little  as  possible 
on  the  anterior  part  of  the  vessel.  To 
accomplish  this  we  require  an  easy  bow, 
which  cannot  be  obtained  without 
length.  This  point  is  conceded  on  all 
hands — sage,  sire  and  school-boy  will 
admit  this,  and  the  theorist  himself  will 
not  deny  its  truth.  Let  this  be  set 
down  as  an  axiom,  and  what  inevitably 
follows  ?  Why,  another  truth,  equally 
as  clear,  that  the  current  should  be  in- 
creased on  all  and  on  every  portion  of 
the  posterior  part  to  the  greatest  possi- 
ble extent  consistent  with  nature's  law 
for  fillino-  a  vacuum  in  the  shortest 
possible  time.  Is  it  not  plain,  that  if 
Ave  would  reduce  the  minus  pressure 
on  the  stern  of  a  ship,  we  must  increase 
the  current?  and  the  less  time  required 
for  a  molecule  to  pass  from  the  greatest 
transverse  section  to  the  rudder,  the 
smaller  will  be  the  amount  of  minus 
pressure  consequent  upon  the  revolu- 
tions of  that  molecule  ;  and  farther,  if 
they  are  required  to  move  a  certain  dis- 
tance  in   a   given    time,  their   motion 


200 


MARINE    AND    NAVAL    All  C  HIT  E  0  T  I'  |{  E  . 


must  be  uniform.  We  would  next  in- 
quire of  the  theorist  whether  the  earth's 
path  furnishes  flic  line  that  is  best  cal- 
culated to  accomplish  this?  and  whe- 
ther the  operation  would  be  precisely 
the  same  on  the  posterior  part,  if  a  ball 
were  projected  in  air  or  water  ?  If  the 
molecules  ofthe  water  were  elastic. like 
air,  would  they  not  be  flattened  by  the 
compression  consequent  upon  the  appli- 
cation of  power  in  forcing  a  body  on- 
ward ?  and  if  so,  would  they  be  as  well 
adapted  to  filling  up  the  measure  of  their 
usefulness  on  the  posterior  part  ?  and 
would  not  the  increase  of  current  on 
the  posterior  part  rather  be  calculated 
to  retard  than  to  increase  their  pro- 
gress, when  thus  flattened  by  the  col- 
lision ?  These  questions  theorists  should 
be  able  to  answer  from  theory  alone, 
before  venturing  to  define  or  determine 
the  shape  of  vessels  designed  for  navi- 
gating the  ocean.  Experiments  upon 
the  ocean  by  practical  men  have  solved 
those  problems  beyond  question  or  cavil. 
We  frankly  admit  that  there  are  many 
questions  yet  to  be  determined,  that 
have  not  been  disposed  of  by  practical 
men,  and  perhaps  will  not  be  for  ages ; 
but  we  say  that  the  earth's  path  does 
not  furnish  a  shape  adapted  to  high 
speed.  Mr.  Russell's  wave  principle 
approximates  much  nearer.  In  Plate 
11  we  have  given  an  illustration  ofthe 
form  of  each  end  of  the  line  of*  flotat  ion 


in  strict  conformity  to  the  earth's  path, 
as  the  theory  contemplates  the  same 
shape  on  both  ends  ofthe  vessel.  We 
have  assumed  the  following  dimen- 
sions— length  170  feet;  breadth  '57 
feet  4  inches;  and  applied  the  hall- 
breadths  in  the  following  manner,  by 
dividing  them  into  12S  equal  parts 
on  the  dead-flat  frame.  The  distance 
from  that  point  to  the  bow  may  be  di- 
vided into  16  equal  parts,  at  each  of 
which  the  following  would  be  the  half- 
breadths,  commencing  at  the  forward 
perpendicular,  which  will  be  found  to 
require  1  part,  and  its  half-breadth 
would  equal  *$*  The  next  would  re- 
quire 4  parts,  and  woidd  equal  '^.  The 
next  would  call  for  9  parts,  equal  to 
ife3i;  16  parts  would  be  the  half-breadth 
ofthe  next,  equal  to  2*33;  the  next.  25 
=to  3*&,  36  follows=5^,  49=^,  64 

feet      >~f\  feet        /-VQ  feet        -t  aq  fei  I         1  in 

=  9.335   '"=11.525  ^=13.425   ^"^=15.025   H* 
feet  1  1  O  fcet  1  O   I  ^Bci  1  OT 

=  1G.335    AA»=i7.3S,    l.£J::=1s.os5    1^«=18.52j 

12S  or  ®  =  1s',!g.  Thus  we  have  given 
the  half-breadths  at  each  one  of  the 
sixteen  settings-off. 

It  is  assumed  by  the  projectors  of 
this  scheme  for  modelling  vessels,  that 
inasmuch  as  inertia  forms  all  the  re- 
sistance that  is  worthy  of  notice,  it  fol- 
lows that  resistance  may  be  measured 
on  any  vessel  built  in  accordance  with 
the  provisions  of  this  theory  ;  but  we 
have  seen  nothing  in  theory  or  prac- 
tice to  furnish  data  ofthe  resistance,  or 


MARINE    AND    NAVAL    ARCHITECTURE. 


201 


the  power  required  to  overcome  it. 
By  this  system  the  inertia  of  the  cur- 
rent on  the  bow,  must  of  necessity  be 
equal  to  that  of  the  stern — a  result  not 
sustained  by  experience.  Much  de- 
pends upon  the  application  of  the  pro- 
pelling power,  the  leverage,  &c.  Mo- 
tion in  vessels  may  be  regarded  to  some 
extent  as  analogous  to  the  law  of  mo- 
tion in  mechanics.  An  increase  of 
speed  is  at  the  expense  of  power ;  but 
the  diminution  of  power  is  much  more 
rapid  on  sea  than  on  land. 

We  have  shown  on  Plate  11a  form 
much  better  adapted  to  the  purposes 
of  speed  for  the  after  end  of  a  ship 
than  that  we  have  already  described ; 
and  having  had  some  little  experience 
in  forming  shape  for  high  speed,  we 
hesitate  not  to  say  that  the  latter-form- 
ed line  of  flotation  will  allow  the  water 
to  close  up  the  cavity  with  more  force 
than  the  former  shape,  and  not  only  so, 
but  the  equilibriations,  which  must  of 
necessity  take  place  on  the  after  end, 
are  more  rapid.  The  formation  of  this 
line  accords  with  the  theory  in  one 
particular  only.  The  divisions  are 
made  in  the  same  manner,  but  the  pro- 
portions are  not  correct.  We  have 
applied  whole  breadths  at  the  same  set- 
tings-off that  we  applied  half-breadths 
in  the  former  case.  The  proportion- 
ate dimensions  assumed  for  the  practi- 
cal application  of  the  theory,  are  better 


or  more  favorable  for  its  adherents  than 
those  in  general  use.  170  feet  on  load- 
line,  or  between  perpendiculars,  is  sel- 
dom connected  with  a  beam  of  37  feet 
4  inches.  Ships  (with  few  exceptions) 
have  a  less  proportion  of  beam,  which 
would  extend  the  breach  or  discrepan- 
cy still  farther  into  this  theory  ;  or 
while  it  would  operate  more  favorable 
for  the  bow,  it  would  operate  less  fa- 
vorable on  the  stern.  It  will  require 
but  a  moment's  reflection  to  discover, 
that  if  the  two  ends  of  a  vessel  are  re- 
quired to  be  alike  in  shape  for  speed, 
the  fluid  should  be  alike  circumstanced 
on  the  two  ends.  No  one  will,  we  are 
persuaded,  call  in  question  this  dogma  ; 
and  if  true,  is  it  not  equally  true  that 
the  fluid  is  not  alike  in  condition  on  the 
two  ends?  Will  any  one  doubt  that 
the  water  is  more  disturbed  on  the  after 
end,  or  after  having  passed  the  great- 
est transverse  section,  than  at  the  for- 
ward perpendicular  ?  We  think  this 
position  is  also  to  be  maintained. 
Then  it  is  equally  clear,  that  if  the 
water  is  more  disturbed  on  the  pos- 
terior than  on  the  anterior  part,  it  is 
also  less  buoyant,  and  if  there  is  less 
buoyancy  in  the  water  on  the  after 
end,  there  should  be  more  buoyancy  in 
the  vessel;  if  not,  what  is  the  result  I 
why,  at  high  speed  the  vessel  settles  by 
the  stern|  and  draws  more  water  alt 
than  when  at  rest.      Here  we  see  that 

2<i 


202 


MARINE    AND    NAVAL    ARCHITECTURE. 


universal  law  of  motion  carried  out 
fully.  An  increase  of  speed  is  at  the 
expense  of  power,  and  this  is  true  both 
with  regard  to  the  vessel  and  the  water. 
As  the  water  becomes  less  buoyant,  its 
current  must  be  increased,  in  order 
that  we  may  maintain  the  same  amount 
of  buoyancy  ;  and  although  about  the 
same  amount  of  resistance  is  encoun- 
tered by  the  application  of  an  equal 
amount  of  power,  yet  the  speed  is  the 
regulator;  and  were  we  to  admit  that 
the  same  amount  of  power  applied  on 
two  vessels  would  create  an  equal 
amount  of  resistance  on  the  bow,  it 
would  not  follow  that  the  speed  would 
be  alike  in  both  vessels  ;  and  the  vessel 
that  had  attained  the  greatest  speed 
might  have  had  the  fullest  bow  and  the 
best  after  end  for  restoring  the  water 
l.o  its  former  equilibriated  state.  Many 
neu  of  experience,  and  even  ship-build- 
ers, think  that  it  cannot  be,  that  we  are 
familiar  with  the  results  of  experience 
in  this  country,  else  we  would  not  ad- 
vocate the  full  after  end.  It  is  for 
this  very  reason  that  we  are  found 
where  we  are  on  this,  as  on  many  other 
points  connected  with  building  ships. 
If  our  ships  are  required  to  sail  no 
faster  than  they  did  thirty  years  ago, 
then  we  say  the  fore  end  the  fullest,  or 
the  full  bow  and  the  lean  after  end  ; 
l»iit  if  our  freighting  ships  are-expected 
to  sail    faster,  and    at   the    same  time 


carry  as  much  or  more,  they  must 
have  a  different  shape  ;  and  if  we  would 
maintain  our  supremacy  in  this  particu- 
lar, we  must  adopt  such  measures  as 
will  secure  those  advantages  to  our- 
selves that  nature  has  placed  within 
our  reach.  Talk  about  the  full  after 
end  to  a  ship  for  speed,  and  the  ship- 
builder stands  aghast ;  his  thirty  years' 
experience  repudiates  the  idea ;  the 
captain  cries  out,  "  preposterous  !  she 
won't  steer:"  this  is  the  watch-word 
that  is  passed  along,  and  finds  a  re- 
sponse throughout  the  ship-yard  and 
throughout  the  ship.  From  those  two 
channels  emanate  what  may  emphati- 
cally be  termed  the  inertia  of  public 
opinion  with  regard  to  the  proper  for- 
mation of  vessels.  How  essential  then 
it  is  that  our  ship-builders  and  ship- 
masters should  be  scientific  as  well  as 
practical  men.  We  cordially  agree 
that  their  views  are  correct  as  to  the 
shape  for  moderate  speed  ;  but  let  it 
be  remembered,  that  the  commercial 
world  are  not  content  at  moving  at  the 
same  pace  they  did  some  thirty  years 
ago.  9  knots  by  the  wind  will  not  do 
for  the  middle  of  the  nineteenth  cen- 
tury. Neither  will  the  same  shape 
answer  for  high  speed  that  we  have 
made  for  a  more  moderate  speed.  We 
mean  the  same  proportions  in  shape  ; 
that  is  to  say,  if  20  per  cent,  of  buoy- 
ancy is  taken   off  the  fore-body   to  in- 


MARINE   AND    NAVAL    ARCHITECTURE. 


203 


crease  the  speed,  it  does  not  follow  that 
20  per  cent,  of  the  buoyancy  should 
also  be  removed  from  the  after  bodv. 
Many,  however,  are  ignorant  of  what 
kind  of  fullness  we  mean,  when  we  say 
that  for  high  speed  vessels  should  be 
fuller  aft.  It  is  well  known  by  many 
ship-builders,  that  on  many  of  our  sharp 
vessels  the  water  rushes  to  the  surface 
from  below  before  it  reaches  the  rud- 
der. The  consequence  is,  that  the 
vessel  settles  ;  she  is  not  sustained  long 
enough.  If  the  vessel  was  so  formed 
belowas  to  conduct  the  retiring  columns 
farther  aft,  she  would  not  settle  ;  the 
water  would  be  conducted  with  more 
force  to  the  rudder,  which,  so  far  from 
making  her  steer  worse,  would  cause 
her  to  steer  much  better — so  much  so, 
that  in  many  cases  one-half  of  the  rud- 
der would  accomplish  all  we  could  de- 
sire ;  for  it  is  plain  even  to  a  prejudiced 
mind,  that  when  a  vessel  is  very  sen- 
sitive at  the  helm,  she  has  too  much 
rudder ;  but  this  advantage  would  be 
seen  and  felt  more  particularly  in  scud- 
ding, when  the  rudders  of  most  vessels 
seem  at  times  to  be  powerless.  This 
tendency  to  settle  aft  in  vessels  as  now 
found,  when  forced  to  a  speed  beyond 
that  to  which  they  are  adapted,  is  rare- 
ly seen,  for  this  reason — sailing  vessels 
are  more  or  less,  under  all  circum- 
stances, affected  in  their  trim  by  the 
leverage  which   conceals  this  tendency 


by  counteracting  it,  and  causing  them 
to  set  by  the  head  ;  and  we  have  known 
reputed  fast  sailers  of  the  old  form  to 
be  3  feet  by  the  head  when  under  a 
press  of  sail ;  whereas  the  same  ship 
when  relieved  from  the  leverage  of  sail, 
would  be  1  foot  by  the  stern.  Hence 
we  say  this  discrepancy  is  rarely  dis- 
covered ;  but  under  some  circum- 
stances it  is  to  be  seen  when  the  effect 
of  the  leverage  is  directly  abeam,  and 
the  ship  is  fully  up  to  her  speed.  In 
steam-vessels  it  is  often  seen,  although 
the  shaft  is  high  above  the  centre  of 
buoyancy,  which  (unless  the  discrepan- 
cy were  of  some  magnitude)  would 
tend  to  elevate  the  stern  and  depress 
the  bow. 

In  endeavoring  to  tinfpld  the  discre- 
pancies of  one  of  the  most  plausible 
theories  yet  advanced  for  the  formation 
of  vessels  ;  and  in  showing  the  extent 
of  this  inertia  of  public  opinion  in  this 
branch  of  mechanical  skill,  we  are  not 
disposed  to  take  aught  from  the  well- 
earned  reputation  of  American  ship- 
builders, who  have  done  much  to  im- 
prove the  complexion  of  American 
commerce  ;  but  we  do  say,  that  were 
scientific  knowledge  as  universally  dif- 
fused among  them  as  it  should  be,  ship- 
building would  no  longer  be  regarded 
as  a  dark,  mysterious,  and  half-de- 
veloped system, but  as  the  most  brilliant, 
harmonious,  and  beautiful  of  all  sys- 


204 


MARINE    AND    NAVAL    ARCHITECTURE. 


terns,  rising  like  new  Cijthera  from 
the  enchanted  wave.  We  should  not 
so  often  hear  the  direful  tidings  that 
are  now  wafted  on  almost  every  breeze, 
of  the  wreck  of  that  surge-beaten  bark 
having  been  swallowed  up  amid  the 
mountain-crested  billows  of  that  dark 
abyss  !  that  heart-rending  news  would 
not  so  often  break  upon  our  ear,  that 
our  friend  or  kindred  has  found  a  wind- 
ing-sheet beneath  that  dark  blue  wave. 
The  silent  foot-fall  of  time  has  thrust 
us  across  the  thresh  hold  of  an  era  in 
which  the  car  of  lightning  mounts 
its  frictionless  wheels,  and  is  spurred 
onward  by  commercial  enterprise. 
Every  other  subject  within  the  grasp  of 
thought  has  contributed  its  quota  to- 
ward the  onward  progress  of  commer- 
cial science  but  that    of  ship-building. 

The  pages  of  this  chapter  have  been 
thus  far  devoted  entirely  to  shape ;  we 
deem  it  necessary  to  follow  other  theo- 
ries of  the  present  time,  inasmuch  as 
it  will  doubtless  be  admitted  that  there 
can  be  no  progress  without  a  know- 
ledge of  the  past,  it  is  equally  apparent 
that  we  must  know  all  that  is  worth 
knowing  of  the  present. 

From  the  days  of  Archimedes  to  the 
present  there  never  has  been  a  time 
when  the  world  was  not  indebted  to 
some  zealous  adventurer  in  this  branch 
of  commercial  science.  Many,  how- 
ever, have  lived  and  died  with  no  wider 


extension  of  their  fame  than  the  orbit 
of  a  few  leagues  from  the  spot  that  gave 
them  birth ;  and  from  the  palmiest 
days  of  the  Syracusan  philosopher  to 
the  middle  of  the  nineteenth  century, 
not  one  single  theorist  has  accomplish- 
ed anything  worthy  of  the  name, 
without  practical  knowledge.  In  more 
modern  times,  we  have  an  illustration 
given  by  Colonel  Mark  Beaufoy,  in  a 
series  of  experiments  from  the  year 
1793  to  179S,  upon  the  solid  of  least 
resistance  ;  the  results  of  which  have 
been  of  no  value  to  the  science  of 
building  ships  ;  and  although  the 
amount  of  labor  attendant  or  conse- 
quent on  such  a  series  of  experiments 
can  scarcely  be  conceived,  yet  a  more 
uninteresting  scientific  work  of  near 
700  pages,  was  perhaps  never  published 
in  the  English  language,  having  not 
the  most  remote  connection  with  that 
branch  of  commercial  science  which 
exhibits  either  natural  or  mechanical 
philosophy  in  building  ships.  In  those 
experiments  the  solids  have  scarcely 
the  least  analogy  to  the  form  of  ves- 
sels, and  were  submerged  six  feet  be- 
neath the  surface  of  the  water  ;  but 
however  destitute  this  volume  may  be 
of  practical  utility,  there  is  another  of 
much  smaller  dimensions  that  seems  to 
demand  a  passing  notice  ;  not  that  we 
consider  ourselves  in  the  light  of  re- 
viewers   of  works  upon  the  science  of 


MARINE    AND    NAVAL    ARCHITECTURE, 


205 


ship-building,  but  because  we  have  un- 
dertaken to  connect  science  with  prac- 
tice in  building  ships,  and  as  a  conse- 
quence find  it  very  essential  to  know 
what  has  been  done  before  we  can  de- 
termine what  may  be  done ;  and  it 
would  have  been  well  if  the  letter  to 
the  author,  found  on  page  93,  could 
have  been  published  centuries  ago  ; 
doubtless  many  would  have  been  dis- 
suaded from  wasting  time,  talent,  and 
money,  in  fruitless  efforts  to  set  the 
world  aright  by  beginning  at  the  wrong 
end, by  substituting  theory  for  practice. 
We  should  have  been  content  to  have 
ended  this  chapter  without  entering 
upon  an  analysis  of  the  most  promi- 
nent features  of  a  patent  ship,  a  model 
of  which  was  exhibited  in  London  in 
1849,  by  Captain  Zerman,  a  naval 
officer  of  thirty-six  years'  experience. 
On  examining  the  details  of  this  patent 
ship,  we  were  involuntarily  led  to  ex- 
claim— if  knowledge  wfcre  commensu- 
rate with  experience,  and  experience 
with  age,  the  present  generation  would 
be  wise  indeed  !  It  cannot  be  regarded 
as  a  digression  from  the  legitimate  sub- 
jects  set  apart  for  this  chapter  to  fol- 
low Captain  Zerman  through  the  mys- 
terious labyrinth  of  inconsistencies  with 
which  the  pamphlet  explaining  the 
principles  and  setting  forth  the  advan- 
tages of  this  patent  ship  abounds,  and 
shall  notice  such  parts  as  more  particu- 


larly pertain  to  shape.     The  Captain 
inducts  his  readers  into  the    merits  of 
this  new  system  of  building  ships,  that 
has  cost  him  twenty  years'  labor,    by 
pointing    to    the    rapid    and    gigantic 
strides  made  in  the  science  of  astrono- 
my, and  its  application  to  nautical  pur- 
poses, aided  by   the    discovery  of  the 
mariner's  compass,  and  the  iron  sinews 
of  the  steam-engine  for  the  purposes  of 
propulsion.      In  fact  man  may  almost 
be  said    to  have   overcome  wind  and 
tide  in  traversing   the  deep;   but   with 
all  these   improvements    in    navigation 
and    propulsion,   there  are    still   over- 
whelming  dangers,  numberless  evils 
and  inconsistencies  to  which  all  ves- 
sels are   exposed    and   subjected  ;  the 
truth  of  which  he  tells  us  is  sadly  illus- 
trated by  the  shipwrecks  which  are  so 
frequent.       Indeed,    Captain    Zerman 
himself  refuses  to  enter  into  a  detailed 
description   of  the    evils  and   dangers 
which    surround  the    mariner  on    the 
sea,   consequent   upon    the  manner   in 
which  vessels  are  and  have  been  con- 
structed, from  the  earliest  dawnings  of 
civilized  life  down  to  the  perfection  of 
modern    times;   they,  by  Captain  Zer- 
man's    history,  have  been  constructed 
upon  the  same   fundamental  principle, 
the   basis  of   which    has    been   a  keel. 
From    time  immemorial    the  keel  has 
been  deemed  as  necessary    for   a  ship, 
as  a  spine  for   the   human  frame  ;   but 


206 


MARINE    AND    NAVAL    ARCHITECTURE. 


the  author  of  this  stupendous  (mis-) 
improvement  in  building  ships,  tells  the 
commercial  world  that  the  keel  is  the 
great  source  of  most,  if  not  all,  the  evils 
attending  the  navigation  of  the  seas. 
But  we  will  allow  this  inventor  to  speak 
for  himself.  Says  he,  it  is  obvious  that 
a  ship  constructed  with  a  keel  takes 
an  enormous  draught  proportionately 
to  her  tonage ;  and  notwithstanding 
her  depth  of  keel,  she  has  no  natural 
or  intrinsic  stability,  since  she  cannot 
go  out  of  the  harbor  without  either 
ballast  or  a  proper  cargo.  This  ballast 
<>ives  her  an  artificial  or  extrinsic  sta- 
bility,  and  from  these  two  defects  (enor- 
mous draught  and  extrinsic  stability) 
naturally  and  inevitably  follow  all  the 
evils,  difficulties,  and  dangers  of  the 
present  system  of  ship-building-  and 
navigation.  He  thenproceedstofurnish 
the  catalogue  :  the  continual  rolling  and 
pitching,  which  shakes  the  whole  frame, 
and  tends  to  weaken  it,  and  in  con- 
tinuous storms  causes  leakage,  which 
may  tend  to  loss ;  the  drifting  of  the 
ship  with  head  winds,  when  she  can 
only  advance  by  tacking  or  veering, 
which  renders  her  voyage  much  longer, 
and  is  sometimes  driven  ashore,  or 
upon  rocks;  the  necessity  of  deep 
water  for  ships  of  largo,  and  even  for 
those  of  small  tonage,  which  increases 
the  danger,  and  prevents  her  from 
navigating  numberless  rivers;  creates 


additional  expenses  in  loading  and  un- 
loading ;  entails  the  necessity  of  taking 
in  ballast  and  throwing  it  away,  which 
incurs  a  great  loss  of  time  and  money, 
and  is  often  attended  with  the  greatest 
difficulty ;  which  ballast,  moreover,  is 
unproductive  dead-weight,  and  dimin- 
ishes the  capacity  for  cargo  ;  increases 
the  bulk  of  water  to  be  displaced,  and 
as  a  consequence  the  resistance  to  be 
overcome ;  and  to  the  above  may  be 
added  the  difficulty  of  manoeuvre,  the 
short  average  durability  of  the  ship, 
cost  of  construction,  the  high  rate  of 
insurance,  which  is  proportionate  to 
the  risks  and  dangers  of  navigation. 
Since,  then,  (the  Captain  adds,)  the 
keel  is  the  source  of  so  many  of  the 
dangers  a  ship  has  to  encounter  on  her 
voyage  through  the  seas,  how  is  it  that 
no  one  has  ever  thought  of  preventing 
the  effects  by  removing  the  cause  ? 
Thus  we  discover  the  result  of  theory 
without  practical  knowledge.  The 
author  of  this  discovery  after  twenty 
year's  labor  in  endeavoring  to  over- 
come the  many  almost  insurmounta- 
ble difficulties,  has  discovered  that  if 
one  keel  is  the  cause  of  so  many  dis- 
asters, that  two  keels  would  remove 
the  difficulty  entirely.  We  remember 
never  to  have  read  of  any  scheme  for 
navigating    the    air,    much    less    the 

Oct 

ocean,  so  completely  baseless  as  this  : 
and  did  not  the  patent  and  description 


MARINE    AND    NAVAL    ARCHITECTURE. 


207 


bear  date  of  1849,  we  certainly  should 
not  have  given  the  present  or  the  two 
last  centuries  credit  for  this  discovery. 
The  Captain  carefully  avoids  propor- 
tions, like  most  theorists  ;  they  allow 
the  builder  the  privilege  of  doing  that 
which  they  cannot  do.  If  theory  can  de- 
scribe the  form,  why  cannot  theory  fur- 
nish the  dimensions?  Had  the  Captain 
furnished  his  own  dimensions,  he  would 
have  exploded  his  own  theory  ;  for  it 
must  be  apparent  to  the  least  discerning 
mind,  that  if  any  vessel  were  cut  into 
two  parts  longitudinally  through  the 
centre  of  the  keel,  and  those  parts 
separated  a  proportionate  distance,  and 
planked  up  vertically  as  high  as  the 
load-line  of  flotation,  and  then  both 
parts  united  above  as  one  vessel,  we 
say  it  must  be  apparent,  that  were  the 
ship  in  one  part  as  wide  as  she  is  de- 
signed to  be  in  two,  she  would  perforin 
very  differently.  But  will  any  me- 
chanic believe  that  the  ship  without  the 
keel  would  draw  less  water  in  two 
parts,  more  particularly  after  the 
weight  of  bulk-heads  and  the  bracings 
and  necessary  appendages  for  strength 
have  been  added?  In  a  word,  can  a 
heavy  ship  displace  less  water  than  one 
less  heavy?  But  we  are  told  that  the 
double  vessel  would  have  the  bottoms 
perfectly  flat  :  and  may  we  not  inquire 
if  many  of  our  finest  ships  have  but 
little   rise  to    the    floor,  and  some  none 


at  all  ?  But  we  are  told  that  the  roll- 
ing and  pitching  causes  leakage,  and 
tends  to  weaken  the  vessel.  To  this 
we  reply,  that  the  rolling  and  pitching 
would  affect  a  vessel  in  two  parts  much 
more  than  in  one,  because  the  ship 
would  roll  and  pitch  much  less  were 
she  of  the  same  dimensions  as  another 
divided.  All  things  else  being  equal, 
(we  mean  with  the  inboard  side  of  each 
section  perfectly  straight,)  with  regard 
to  ballast,  we  find  no  difficulty  in  this 
particular  in  a  single  ship,  if  they  have 
beam  enough.  No  freighting  vessel 
need  carry  ballast  if  she  has  a  propor- 
tionate amount  of  beam,  unless  she  is 
freighting  impressed  cotton,  or  very 
light  goods ;  but  how  the  vessel  be- 
comes more  capacious  by  cutting  a 
groove  through  the  centre,  and  letting 
the  water  take  the  place  of  what  would 
otherwise  be  vessel,  we  cannot  tell ; 
nor  do  we  believe  the  Captain  himself 
would  undertake  the  task :  he  only 
tells  us  that  it  is  so,  and  leaves  us  to 
guess  how.  But  again,  we  are  at  a 
loss  to  know  how  the  resistance  is  to 
be  diminished  ;  with  all  the  resistance 
of  the  two  sides,  and  added  to  this  that 
of  those  vertical  parallel  planes  on  the 
inboard  sides,  we  should  say.  if  called 
upon  for  an  opinion,  that  the  resistance 
would  be  increased  at  least  one-third, 
inasmuch  as  the  resistance  on  planes 
is  absolute  as  well  as  lateral.      That  a 


208 


MARINE    AND    NAVAL    ARCHITECTURE 


ship  would   very  materially  lessen  the 
lee-way  in  the  aggregate,  constructed 
in  this  manner,  we  are  unwilling  to  ad- 
mit, notwithstanding  a  plane  is  present- 
ed the  entire  length  of  the  vessel,  and 
the  full  extent  of  the  draught  of  water 
in    depth.     Her  increased    resistance, 
in  connection  with  her  sluggish  move- 
ments when  in  stays,  would,  without 
doubt,  more  than  counterbalance  any 
thing   gained   by   the  increased  lateral 
resistance.     There  are  two  other  points 
to  which  the  Captain  has  also   called 
the  attention  of  the  commercial  world, 
the  first  of  which  is  the  great  durabili- 
ty of  such  vessels ;  but   having   made 
the  announcement,  he  leaves  us  to  de- 
termine in  what  particulars  the  great 
durability  consists,  not  being  careful  to 
enlighten  the  world   upon  this  point ; 
and  if  left  to  determine  for  ourselves, 
we    unhesitatingly    should  decide  that 
vessels  thus  constructed  would  not  be 
even  as  durable  as  under  the  present 
system.     But  the  last  particular  is  that 
of  avoiding  many  dangers — they  are, 
however,    not  specified ;   and    we  are 
again   left   to  feel  our   way   without  a 
light.     That  such  constructed  vessels 
would  not  be  liable  to  more  of  the  nu- 
merous evils  consequent  upon  naviga- 
ting the  ocean,  few  persons  qualified 
for  deciding  we  are  persuaded  would 
readily  assent.     This  mode  of  construc- 
tion  is    decidedly    more   objectionable 


than  the  double  boat  formerly  used  on 
our  ferries,  but  long  since  repudiated, 
although  the  construction  consisted  of 
two  entire  bottoms,  but  this  method  is 
but  two  half-bottoms,  for  the  reasons 
already  named. 

It   has  been   almost   invariably   the 
case,  that  when  persons  introduce  new 
systems  of  construction  for  ships,  they 
are    content    with    exhibiting    all   the 
prominent  parts  of  the  contemplated 
improvements,  but  the  details  of  con- 
struction   are  often    left  discretionary 
with  the  builders.     Just  so  with  Cap- 
tain Zerman's   patent    ship;   he  never 
followed  up  the  consequences  in  detail 
of  such  manner   of  construction,  and 
leaves  the    constructor  to  perfect   his 
outline  or  design.     The  world  is  left  to 
guess  their  way  in  more  than  one  par- 
ticular.    That  there  should  be  a  cavity 
where  the  keel  is  at  present,  they  are 
made  fully    aware;    and  of  its  advan- 
tages they  are  not  kept  in  ignorance. 
But  the  reader  must  come  to  the  sage 
conclusion  from  the  captain's  own  ver- 
sion, that  no  sophistry  can  make  that 
right  which  common  sense  pronounces 
wrong  ;  and  that  less  than  half  of  the 
thirty-six  years  of  the  Captain's  expe- 
rience spent   in  private   maritime  en- 
terprise,   would  have   taught    him  the 
futility  of  his  projected  design.      Few 
men  have  been  successful  in  improving 
the  form  of  vessels,  except  those  who 


MARINE    AND    NAVAL    ARCHITECTURE 


209 


have  become  familiar  with  all  the  de- 
tails of  practice.  As  it  has  been  well- 
observed,  the  man  is  but  poorly  qualified 
to  judge  of  models  who  cannot  make 
one,  and  the  same  may  be  said  of  the 
draft.  Hence  the  importance  of  be- 
coming- familiar  with  the  ground-work 
of  science  before  embarking-  on  its  bois- 
terous tide. 

The  system  we  have  contemplated 
in  this  chapter  under  the  head  of  pro- 
portions conies  as  a  regulator  ;  it  does 
not  arbitrarily  demand  one  form  for  all 
vessels,  nor  yet  the  abandonment  of  the 
fundamental  principles  of  construction. 
With  regard  to  shape,  we  say  the  par- 
ticular object  or  trade  for  which  the 
vessel  is  designed  should,  to  some  ex- 


tent, determine  this ;  and  with  refer- 
ence to  the  location  and  form  of  the 
greatest  transverse  section,  in  addition 
to  what  we  have  already  advanced 
upon  this  subject,  we  will  only  add,  that 
the  speed  must  regulate  its  location, 
and  to  some  extent  its  form.  If  we 
desire  to  attain  the  highest  speed  at- 
tainable, whether  by  the  power  of  wind 
or  steam,  the  greatest  transverse  sec- 
tion should  be  aft  of  the  centre  of 
length  on  the  load-line,  in  which  case 
the  bow  should  be  relieved  of  the  top 
hamper  as  much  as  possible  ;  the 
leverage  should  be  regulated  to  corres- 
pond, else  the  change  would  prove  de- 
trimental rather  than  advantageous. 


210 


MARINE    AND    NAVAL    ARCHITECTURE 


CHAPTER    VII. 

The  Author's  Discovery  in  obtaining  the  Centre  of  Expansion — Its  importance  to  a  Proper  Distribution  nf 
the  materials  for  strength — Continued  expositions  on  tbe  floor. 


In  the  old  world  it  has  been  the  prac- 
tice to  expand  vessels  from  a  base-line 
assumed  to  be  straight,  and  from  which 
all  the  exterior  plans  would  be  project- 
ed. The  entire  exterior  surface  was 
not  only  projected,  but  the  form  and 
length  of  the  plank  were  also  shown  in 
their  proper  places  and  appropriate 
lengths  ;  and  it  is  supposed  to  be  fairly 
assumed,  that  the  proper  shape  as  well 
as  length  was  actually  shown  on  this 
plan  of  expansion,  and  referred  to  in 
planking  for  the  length  and  sometimes 
for  the  shape  of  the  plank.  This  prac- 
tice in  the  United  States  has  been  con- 
fined chiefly  if  not  exclusively  to  the 
several  Navy  Yards,  where  a  board  pre- 
pared for  the  purpose  would  exhibit 
only  the  arrangement  of  the  butts  of 
the  plank  on  the  outside  of  the  ship. 
The  practice  of  exhibiting  the  shape  or 
sni  having  grown  obsolete  to  some  ex- 
tent, in  consequence  of  the  many 
failures  to  exhibit  the  actual  form  of 
the  vessel  in  her  expanded  or  extended 
position,  the  mechanic,  whose  busi- 
ness it  is  to  line  the  plank  to  its  pro- 


per shape,  assumed  that  the  expansion 
plan  furnished  the  actual  shape  :  and 
as  a  consequence  would  select  his  plank 
in  accordance  with  the  amount  of  sni 
furnished  by  the  expansion  plan  :  and 
after  having  been  chagrined  time  after 
time  by  this  deceptive  map  of  the  ex- 
panded vessel,  the  plan  at  length 
has  been  very  generally  abandoned  in 
this  country  at  least  ;  of  its  usefulness, 
however,  there  can  be  but  little  ques- 
tion, if  properly  and  reliably  made. 
It  will  appear  quite  apparent  to  the 
discerning  mechanic,  that  coidd  the 
ship  be  flattened  out  to  a  perfect  plane, 
it  would  not  furnish  a  straight  base- 
line. Let  us  suppose  the  model  show- 
ing half  the  vessel  in  miniature  were 
placed  on  a  plane  with  the  middle-line 
next  to  the  plane  ;  and  for  our  present 
purpose  the  model  may  be  assumed  to 
be  made  of  some  material  that  may 
readily  be  brought  to  a  flat  surface  by 
the  application  of  pressure  ;  when  thus 
flattened  out,  we  may  see  the  actual 
form  of  all  and  every  plank  on  the  ex- 
terior part  of  the  ship.     This  is  vastly 


MARINE  AND  NAVAL  ARCHITECTURE. 


211 


important  to  the  young  mechanic,  in- 
asmuch as  he  may  aspire  to  the  position 
of  leader  in  this  part  of  the  construc- 
tion of  the  ship,  and  should  have  his 
eye  familiarized  with  the  actual  shape 

.of  the  plank,  or  the  shape  required  he- 
fore  he  can  line  it  to   its  proper  form. 

'The  time  was  when  it  was  supposed  to 
be  impossible  to  line  a  plank  by  the  eye, 
particularly  the  fore  and  after  woods. 
It  was  deemed  actually  necessary  to' 
take  a  spiling  from  the  bow  or  stern  to 
obtain  the  proper  shape  ;  but  in  the 
order  of  improvements  that  day  has 
passed,  and  the  practice  has  grown  ob- 
solete. Mechanics  no  longer  think  of 
taking  a  spiling  for  a  plank,  unless  in 
some  very  peculiar  part  of  the  ship, 
where  there  may  be  a  poor  chance  of 
working  it  to  its  berth,  and  only  under 
some  such  circumstances  is  the  prac- 
tice adhered  to  of  spiling  for  any  plank 
on  a  ship,  the  garboard,  fore  and  after 
woods  excepted. 

To  give  in  addition  to  the  actual 
shape  of  the  plank,  the  proper  shift  of 
butts  in  planking,  and  of  their  distri- 
bution in  the  frame,  or  of  the  timber  of 
Which  the  frame  is  composed,  may  per- 
haps be  thought  superfluous  by  some, 
but  as  it  pertains  to  the  systematical 
construction  of  this  stupendous  fabric, 
we  think  the  time  well  spent  by  the 
oung  mechanic  in  endeavoring  to  be- 
come familiar  with  the  means  of  cal- 


y 


dilating  every  particular,  relative  to  the 
quantity  of  strength,  or  its  proper  distri- 
bution, as  well  as  to  the  form  of  the 
ship.  The  utility  of  this  knowledge 
upon  mature  reflection  we  think  will 
not  be  questioned.  With  respect  to 
the  frame  of  a  ship,  it  must  be  apparent 
that  a  good  degree  of  skill  is  necessary 
to  the  proper  disposition  of  the  timber 
of  which  the  frame  is  composed  ;  the 
variety  of  curves  ;  the  different  lengths  ; 
the  diminished  scantling  at  the  extremi- 
ties, as  well  as  at  the  rail  ;  all  contri- 
bute to  make  the  subject  one  of  im- 
portance and  of  interest  to  the  me- 
chanic. This  subject  has  never  been 
made  sufficiently  clear  to  the  minds  of 
the  young  and  inexperienced  ;  hence 
the  necessity  of  pausing  to  inquire  what 
has  been  done  in  order  that  we  may 
know  what  may  be  done.  The 
strength  of  our  vessels  is  a  subject 
worthy  of  our  notice,  more  particular- 
ly when  it  may  be  obtained  without 
additional  cost.  It  will  not  be  neces- 
sary to  enlarge  on  their  importance. 

It  has  been  the  custom  to  determine 
the  scantling  and  arrange  the  butts  of 
the  frame,  or  the  number  of  timbers 
composing  the  frame  of  a  ship  or  other 
vessel,  upon  the  floor  of  the  loft.  The 
dead-flat  frame  being  the  one  usually 
selected  for  this  purpose,  a  batten  being 
bent  to  the  shape  of  the  frame,  and 
the  size  of  the  scantling  set  off  toward 


212 


MARINE   AND    NAVAL    ARCHITECTURE, 


the  centre  at  the  head  of  the  frame, 
and  likewise  the  size  at  the  side  of  the 
keel,  a  batten  is  then  bent  with  those 
boundaries  at  the  head  and  keel,  the 
intermediate  space  being  determined 
by  the  builder.  But  we  apprehend 
this  to  be  a  loose  and  indefinite  mode 
of  determining  the  size  of  the  frame- 
by  the  scantling  size  we  mean  the 
moulding  size  of  the  frame  from  the 
keel  to  the  head  of  the  frames.  The 
dimensions  at  the  keel,  or  the  depth  on 
the  keel,  should  in  all  cases  be  some- 
thing more  than  the  siding  of  the  keel. 
in  steamships  the  difference  should  be 
greater  than  in  sailing  ships,  on  ac- 
count of  the  application  of  power  in 
opposite  directions  ;  that  is  to  say,  if 
the  keel  of  a  steamship  were  sided  18 
inches,  the  depth  of  the  floors  should 
not  be  less  than  20  inches ;  whereas 
the  keel  of  a  sailing  ship,  requiring  a 
siding  size  of  16  inches,  should  have  a 
depth  of  17  to  17g  inches  in  the  throats 
of  the  floors,  or  the  depth  on  the  top 
of  t  he  keel.  These  proportions  will  ap- 
ply to  smaller  vessels,  and  may  be  con- 
sidered sufficiently  heavy,  unless  the 
vessel  be  a  centre-board  vessel,  in  which 
case  the  proportion  will  not  apply. 
Where  light  draught  of  water  is  of 
great  consequence  in  smaller  vessels 
than  ships  and  brigs,  we  may  perhaps 
he  quite  safe  in  reducing  the  size  some- 
w  hat  below  the  proportion  given. 


There  is  still  another  exception  to 
this  general  rule  when  we  determine 
to  cover  the  vessel  with  plank  of  more 
than  usual  thickness.  We  may  in  such 
cases  be  safe  in  departing  from  those 
proportions;  the  usual  proportion  for 
the  head  of  the  frame,  or  at  the  plank- 
sheer,  and  one  which  we  should  our- 
selves adopt,  would  be  one-third  of  the 
size  at  the  keel ;  and  if  the  vessel  be  an 
t)cean  steam-vessel,  a  smaller  ratio  may 
be  adopted,  on  account  of  the  extra 
size  at  the  keel.  Our  reasons  for  re- 
ducing the  scantling  when  the  thick- 
ness of  the  plank  is  increased,  are,  that 
the  strength  of  the  vessel  is  increased 
faster  by  increasing  the  thickness  of  the 
plank  inside  and  out,  or  inside  only, 
than  by  adding  to  the  scantling  of  the 
frame  ;  and  one  of  two  methods  of  re- 
ducing the  frame  may  and  should  be 
adopted  when  we  determine  to  add 
materially  to  the  thickness  of  the  plank, 
either  to  spread  the.  frames  farther 
apart,  or  reduce  the  scantling  size. 
It  may  be  supposed  that  a  reduction  of 
the  siding  size  of  the  frame  would  have 
the  same  effect,  which  to  some  extent 
is  true;  the  weight  would  be  reduced, 
which  is  a  secondary  consideration 
when  strength  is  to  be  gained.  By  re- 
ducing the  siding  size  of  the  frame,  we 
bring  the  fastening  closer  together  than 
it  should  be  ;  besides  this,  there  are 
more  grains  of  the  timber  cut  off  with 


MAUJNE    AND    NAVAL    ARCHITECTURE. 


213 


an  equal  amount  of  fastening  than 
would  have  been  with  a  smaller  scant- 
ling ;  consequently  more  of  the  strength 
of  the  timber  is  lost,  and  it  also  follows 
that  less  remains.  To  make  this  part 
more  clear,  suppose  the  top  timber  for 
example  to  be  sided  10  inches,  and 
moulded  9  inches  at  a  certain  place, 
we  bore  an  inch  auger  hole  through 
it  thwartships,  is  it  not  clear  that  one- 
tenth  of  the  strength  is  gone?  whereas 
had  the  scantling  size  been  8  and  the 
siding  size  11  inches,  we  shall  discover 
that  we  should  have  had  more  strength 
left,  although  the  hole  for  the  fastening 
was  the  same  in  size.  In  the  first  ex- 
ample  we  had  10x9  inches,  which  gave 
us  90  square  inches  of  transverse  area, 
and  it  would  require  10  of  the  1  inch 
holes  to  cut  off  the  timber,  while  in  the 
second  example  we  have  11x8,  which 
gives  2  square  inches  less  area,  and 
yet  it  requires  11  holes  of  the  same 
size  as  before  to  cut  the  timber  off. 
Thus  it  may  fairly  be  assumed  that 
upon  this  score  alone  it  is  decidedly 
preferable  to  have  more  siding  size  and 
less  scantling  size.  But  there  is 
another  reason  why  we  prefer  more 
size  in  the  siding  and  less  in  the  scant- 
ling— the  thicker  the  planks  are,  the 
more  longitudinal  strength  we  obtain, 
inasmuch  as  an  inch  added  to  the  thick- 
ness of  the  inside  plank,  or  to  the  out- 
side plank,  is  almost  equal  to  sheathing 


a  vessel,  which  it  is  readily  conceded 
is  a  great  addition  to  the  strength;  the 
extra  thickness,  however,  in  the  out- 
side plank,  is  the  most  advantageous  on 
account  of  the  caulking,  which  by  in- 
creasing the  surface  of  oakum  in  the 
seams,  renders  the  increased  thickness 
of  somewhat  more  service.  But  again, 
we  would  make  a  still  greater  reduc- 
tion in  the  scantling  size,  and  also  re- 
duce the  siding  size  of  the  lower  flit- 
tocks  at  the  ends  of  the  ship;  this  is 
rendered  necessary,  it  will  be  at  once 
perceived,  for  two  reasons  :  first,  we 
shall  have  much  more  timber  than  in 
other  parts  of  the  ship — a  difficulty 
which,  without  this  precaution,  we  can- 
not avoid,  inasmuch  as  the  contraction 
consequent  upon  the  shape  of  the  ends 
of  the  vessel  leaves  less  room  for  the 
distribution  of  timber  below,  while 
above  we  have  more  room  than  we  re- 
quire ;  and  if  the  siding  size  of  the 
timber  in  the  futtocks  of  the  cauls 
were  to  remain  as  in  other  parts  of  the 
ship,  with  but  a  single  timber  below, 
both  forward  and  aft,  it  would  be  a 
much  better  arrangement  than  at  pres- 
ent, and  our  ships  would  be  stronger 
and  last  much  longer  than  they  now 
do  at  those  parts,  particularly  those 
built  of  white  oak  at  the  extremities. 
But  there  is  still  another  feature  to  this 
question  that  has  not  been  shown:  there 
are  two  timbers  in  each  frame  that  ex- 


214 


MARINE    AND    NAVAL    ARCHITECTURE 


tend  from  the  keel  to  the  head  of  the 
frame,  with  joints  or  butts  at  regular 
intervals.  It  must  be  quite  clear,  that 
at  those  butts  the  frame  has  but  a  sin- 
gle limber  as  it  regards  strength;  that 
is  to  say,  one  timber  of  the  frame 
being  cut  off  here,  the  frame  is  only 
equal  to  the  strength  of  a  single  tim- 
ber; hence  the  importance  of  having 
as  few  of  those  weak  parts  to  the  frame, 
and  of  keeping  those  places  as  far  apart 
as  possible,  longitudinally  as  well  as 
vertically.  But  it  may  have  been  sup- 
posed, that  although  the  in  and  out 
fastening  would  seem  to  call  for  a  re- 
duced scantling,  and  an  increased  sid- 
ing size  to  the  frame,  yet  when  the 
frame-bolts  are  brought  into  the  ac- 
count, the  advantages  would  not  seem 
to  be  so  great.  To  this  question  we 
apply  the  same  answer  as  to  the  form- 
er, viz. :  the  increased  thickness  of  the 
plank  will  more  than  make  up  the  de- 
ficiency ;  but  we  have  told  our  readers 
that  the  ship  would  be  stronger  with 
less  timber  :  this,  although  seemingly 
paradoxical,  is  nevertheless  true.  It  is 
a  truism  that  is  at  once  recognized  by 
every  mechanic — that  to  increase  the 
bulk  of  materials  beyond  what  is  ne- 
cessary to  increase  the  strength,  rather 
weakens  the  ship  than  otherwise,  inas- 
much as  the  increased  strength  ope- 
rates against  the  weaker  parts,  and 
causes  those  parts  to  yield  more  than 


they  otherwise  would  yield  ;  besides 
this,  it  must  be  quite  apparent  that  the 
ends  are  the  strongest  parts  of  the  ves- 
sel.  Tinder  any  circumstances,  when 
the  usual  mode  of  construction  is  adopt- 
ed, the  deadwoods  are  a  source  of  great 
strength  to  the  part  of  the  ship  in  which 
they  are  located.  It  will  also  be  re- 
membered, that  the  proportionate 
amount  of  cargo  is  small  that  the  ends 
will  contain,  when  this  increased 
strength  is  considered  ;  and  again,  that 
the  leverage  of  the  masts  and  rigging 
are  not  even  proportionately  sustained 
here,  so  that  we  need  have  no  fears  in 
relation  to  the  strength  of  the  ends; 
and  still  another  reason  exists  for  di- 
minishing the  scantling  at  the  ends  of 
the  vessel — the  plank  is  usually  dimin- 
ished in  thickness  at  the  ends  of  the 
ship,  and  if  it  is  not,  it  should  be,  inas- 
much as  an  equal  thickness  of  plank 
with  that  of  other  parts  of  the  ship, 
cuts  too  deep  a  rabbet,  which  exposes 
the  fastening  in  the  stem  and  stern-post, 
or  makes  it  necessary  to  place  all  the 
fastening  in  the  centre  of  the  stem  and 
post,  which  does  not  add  strength  in 
proportion  to  the  number  of  bolts  con- 
tained, unless  properly  distributed;  and 
it  should  be  an  invariable  practice  to 
make  the  rabbet  of  less  depth  on  the 
stem  and  stern-post  and  dead-woods 
than  on  the  keel ;  not  because  the  keel 
does  not   require  as   much   support  for 


MARINE    AND   NAVAL    ARCHITECTURE. 


215 


the  floors  and  spread  for  the  fastening 
as  the  stem  and  post,  but  because  the 
rabbet  on  the  keel  cuts  but  little  com- 
pared with  the  ends.  On  the  keel,  par- 
ticularly along  midships,  the  angle  of 
dead-rise  (on  freighting  ships  particu- 
larly) differs  but  little  from  that  of 
square  with  the  side  of  the  keel,  or  of 
right  angles  ;  consequently  to  make  a 
square  seam,  we  require  but  the  differ- 
ence between  the  angle  of  rise  and 
square,  or  of  right  angles,  in  the  thick- 
ness of  the  plank  as  the  depth  of  the 
rabbet ;  but  on  the  stem  and  post  the 
case  is  quite  different :  the  rabbet  cuts 
more  transversely,  and  consequently 
deeper,  leaving  less  wood  between  the 
two  rabbets  transversely ;  hence  the 
importance  of  reducing  the  rabbets  on 
the  ends  of  the  vessel ;  and  on  sharp 
vessels  it  is  also  necessary  to  increase 
the  siding  size  of  the  keel,  in  conse- 
quence of  the  increased  depth  of  the 
rabbet  ;  the  siding  size  of  the  keel 
should  be  with  the  builder  a  matter 
that  his  own  judgment  or  experience 
should  determine.  It  cannot  be  sup- 
posed that  every  matter  of  this  nature 
is  determinable  by  rule  ;  as  no  propor- 
tion of  the  dimensions  of  the  ship  would 
be  safe  to  adhere  to  as  a  standard. 

We  have  said  that  the  scantling 
should  be  smaller,  and  the  rabbets  less 
deep  at  the  ends,  because  they  were 
the   strongest  parts   of  the   ship  ;  but 


the  plank  at  the  ends  should  also  be 
thinner  ;  they  should  be  diminished  at 
the  end  to  the  thickness  shown  by  the 
depth  of  the  rabbet,  and  tapered  as  far 
from  the  end  as  is  required  to  make 
the  thickness  a  fair  taper. 

Having  shown  the  relative  propor- 
tion that  should  exist  between  the  head 
and  heel  of  the  frames,  or  the  scant- 
ling size  at  those  points,  and  also 
thrown  the  builder  upon  his  resources 
in  relation  to  the  siding  size  of  the  keel, 
(not  however  without  first  telling  him 
that  the  depth  should  be  considered  as 
bavin"-  some  relative  connection  with 
the  siding  size,)  and  believing  that  we 
do  him  a  service  by  thus  leaving  the 
matter  with  him,  seeing  there  are  a 
variety  of.  circumstances  that  would 
require  a  departure  from  any  propor- 
tions that  might  be  given,  we  next 
come  to  the  manner  of  determining  the 
size  between  the  head  and  heel  of  the 
frame,  or  the  scantling  between  those 
points. 

It  has  been  a  practice  in  some  parts 
of  Europe  to  sweep  in  the  dead-flat 
frame  upon  the  floor  of  the  loft,  and 
strike  up  the  middle-line  in  the  body- 
plan,  from  which  the  scantling  size  at 
the  head  is  set  off  at  its  proper  height, 
as  shown  in  Plate  12.  The  size  be- 
in"  also  set  off  below,  a  line  is  stricken 
on  the  floor  from  spot  to  spot,  and  the 
space  between  those  lines   shows  the 


216 


MARINE    AND    NAVAL 


TECTURE, 


scantling  size  of  the  frame,  and  is  ob- 
tained as  follows  :  the  middle-line  is 
divided  into  a  convenient  number  of 
spaces,  and  the  0  frame  is  likewise 
divided  into  a  like  number  of  equal 
parts,  and  lines  being  drawn  from  one 
to  the  other,  or  from  the  middle-line  at 
the  upper  spot  to  the  frame  on  the  up- 
per spot,  furnishes  the  place  where  the 
size  is  to  be  taken  at  the  middle-line 
and  applied  to  the  frame.  This  method 
is  adopted  in  the  United  States  when 
any  method  is  adhered  to,  which  is  not 
always  the  case.  We  may,  by  the 
adoption  of  this  mode,  regulate  the 
scantling  size  as  we  please,  with  this 
exception:  it  does  not  provide  for  a 
reduction  at  the  extremities,  which  is 
its  most  objectionable  feature  ;  that 
however  may  be  remedied  by  making 
the  diagonal  lines  curved  instead  of 
straight  lines,  as  shown  by  the  dotted 
line  in  Plate  12,  which  may  be  so  ar- 
ranged as  not  to  affect  the  square  body, 
and  apply  only  to  the  cants.  If  we  re- 
quire a  larger  scantling  size  between 
the  head  and  heel,  we  may  drop  the 
inboard  end  of  the  diagonal,  or  we  may 
extend  the  diminishing  line  higher,  and 
aoain  divide  the  length  on  the  middle- 
line,  keeping  the  head  and  heel  the 
same  as  before.  After  having  deter- 
mined the  scantling  size,  the  lines 
may  remain  on  the  floor,  and  the  sizes 
may   be    marked   to    correspond  with 


dead-flat  mould  on  all  the  other  or  the 
remaining  moulds  in  the  same  body  at 
the  place  where  the  diagonal  crosses 
the  moulding  or  outer  edge  of  the 
mould.  The  diagonals  need  not  inter- 
fere with  others  that  may  be  on  the 
floor  for  bevelling  spots,  if  it  is  thought 
that  they  are  likely  to  ;  they  may  be 
marked  with  pencil  to  distinguish  them, 
as  the  diagonals  for  the  bevels  and  for 
arranging  the  butts  are  usually  shown 
with  white  chalk. 

Having  shown  the  appropriate 
method  of  arranging  the  size  of  the 
material  for  strength  longitudinally, 
and  in  part  diagonally,  we  may  find  it 
to  our  advantage  to  inquire  what  can 
be  done  to  strengthen  the  ship's  frame, 
and,  as  a  consequence,  the  whole  fabric 
vertically.  We  have  already  shown 
that  the  ship  is  but  single-timbered  in 
the  direction  of  the  diagonals,  and  by 
which  the  length  of  the  timbers  are  de- 
termined, while  from  that  point  to  the 
next  butt,  the  ship  is  double-timbered; 
and  this  arrangement  is  continued 
throughout  the  entire  ship.  Thus  it 
is  plain  that  at  regular  intervals  there 
are  weaker  places  than  those  above  or 
immediately  below.  Various  measures 
have  been  adopted,  both  in  the  old  and 
new.  world,  to  remedy  this  manifest 
defect  ;  but  thus  far  the  projectors 
have  only  partially  accomplished  their 
purpose.     A  great   variety  of  expedi 


MARINE    AND    NAVAL    ARCHITECTURE. 


217 


ents  have  been  adopted  in  Europe, 
none  of  which  have  found  favor  in 
universally  obviating  this  manifest  de- 
fect in  the  present  system. 

It  will  require  but  a  glance  at  this 
subject  by  the  thinking-man  to  enable 
him  to  discover  that  the  plank  runs 
nearly  in  the  direction  of  the  diagonals 
outside  and  often  inside  of  the  ship  ; 
hence  it  must  be  equally  apparent,  that 
at  every  range  of  butts  the  strength  of 
the  ship  is  less  than  it  might  be  with 
the  same  material,  were  it  but  every 
third  or  fourth  frame  that  displayed  a 
range  of  butts :  in  the  same  direction 
and  at  the  same  place  that  a  seam  in 
the  outside  and  inside  plank  is  shown,  it 
would  be  deemed  of  less  consequence, 
but  this  range  of  butts  is  found  on 
every  frame  at  the  same  place.  It  is 
true  that  measures  are  sometimes 
adopted  to  bring  the  butts  of  the  top- 
sides  under  the  hanging  knee,  or  in  a 
position  in  which  they  are  supported 
by  other  means  than  that  furnished  by 
the  plank ;  but  below  the  decks  and 
han<> in"  knees  there  is  no  extrinsic 
support  beyond  what  is  furnished  by 
the  bilge  strakes,  which  are,  as  they 
should  always  be,  the  thickest  planks 
in  the  ship,  because  the  bilge  is  the 
weakest  part  of  the  ship,  and  cannot 
(without  extra  means  are  adopted)  be 
as  strong   as  other  parts  of  the  struc 


seen  a  range  of  butts  at  the  upper 
edge  of  the  bilge  strakes  of  a  ship,  or 
at  the  upper  cd^e  of  the  water-ways 
between  decks  and  at  the  ends  of  the 
hanging  knees,  which  has  a  tendency 
to  weaken  the  ship  ;  hence  the  truth 
of  what  we  have  already  said  in  sub- 
stance, that  something  more  than  the 
materials  are  requisite  to  the  formation 
of  a  strong  ship.  This  is  one  of  the 
principal  reasons  why  ships  often  work 
at  sea,  but  do  not  show  it  when  in  port. 
Those  butts  and  seams  all  in  vertical 
range,  and  running  in  the  same  direc- 
tion, operate  like  hinges  on  a  door  ; 
the  ship  may  go  and  come  in  this  man- 
ner for  a  length  of  lime,  until  she  hap- 
pens to  be  grounded  on  the  beach,  and 
then  the  story  is  soon  told..  If  a  ship- 
owner should  think  the  picture  loo 
highly  colored,  let  him  adopt  a  course 
we  shall  propose  on  a  ship  that  has  a 
range  of  butts  in  the  frame  of  his  ship, 
at  or  near  the  upper  edge  of  the  lower 
deck  water-ways.  He  may  think  her 
a  strong  ship,  but  let  him  put  in  a  set 
of  standing  knees  between  decks,  load 
his  ship  and  send  her  to  sea,  and  more 
than  likely  the  first  gale  of  wind  will 
break  half  of  those  knees,  and  it  is  very 
reasonable  that  it  should.  The  ship  is 
made  very  strong  above  and  below  this 
weak  part,  and  the  strain  of  the  masts 
and  rigging  operate  in  direct  line  from 


ture;    and  we  have  not  unfrequently  |  the  channels  through  the  lower  deck 

28 


218 


MARINE   AND    NAVAL    ARCHITECTURE. 


partners  to  the  bilge,  and,  as  a  conse- 
quence,  on  any  and  every  weak  part 
between  those  points. 

It  may  not  seem  quite  clear  to  all 
that  the  bilge  should  be  denominated 
the  weakest  part  of  the  frame.  In  re- 
ply to  the  inquiry  why?  we  would  say. 
that  any  and  every  structure  can  be 
made  stronger  with  the  same  amount 
of  materials  in  the  form  of  a  plane,  than 
when  the  frame  or  structure  has  no 
determinate  form  ;  not  only  so,  but  the 
side  of  a  ship  is  strengthened  by  the 
decks  very  much.  This  support  the 
bilge  cannot  have  ;  but  again,  the  bilge 
has  not  only  the  strain  consequent  upon 
its  own  weight,  and  the  pressure  within 
of  cargo,  and  without  of  water,  which 
are  seldom  well  balanced,  but  in  addi- 
tion to  this,  it  has  the  variable  strain 
of  both  the  side  and  bottom  at  the 
same  time  to  withstand,  from  which 
we  may  reasonably  infer  that  Ave  are 
not  far  from  the  truth  when  we  say  that 
the  bilge  of  a  ship,  having  the  butts  of 
the  frame  arranged  as  they  usually  are, 
is  not  as  strong  as  other  parts  of  the 
ship  by  from  10  to  20  per  cent.  The 
harder  the  bilge,  the  weaker  it  is,  and 
the  reverse  is  equally  true. 

We  readily  admit  that  many  build- 
ers do  not  confine  their  butts  to  the 
diagonals,  or  do  not  cut  off*  the  timbers 
by  the  diagonal  lines  ;  but  while  we 
admit  this  fact,  we  must  also  state  the 


reason,  which  is  simply  because  it  is 
not  to  their  interest  to  do  so.  If  a  fut- 
tock  will  work  a  few  inches  longer  than 
the  sirmark,  the  moulder  would  of 
course  save  it  on  the  best  timber, 
whether  it  were  head  or  heel ;  whereas 
it  is  well  known  both  to  the  moulder 
and  the  framer  that  it  will  not  do  to 
depart  a  great  distance  from  the  place 
for  the  butt,  (unless  two  timbers  can  he 
obtained  in  one.)  if  they  do.  the  scarf 
is  made  too  short,  either  above  or  be- 
low :  thus  it  is  plain  that  in  the  main 
the  departure  is  only  the  exception, 
and  not  the  rule.  But  the  bilge  of  a 
ship  seldom  receives  this  advantage  : 
the  timber  being  crooked,  is  hard  to 
find,  and,  as  a  consequence,  a  butt  is 
made  in  the  hardest  part  of  the  crook: 
this  of  course  relieves  the  moulder,  but 
diminishes  the  strength  of  the  bilge. 

The  casual  observer  cannot,  we 
think,  but  admit,  that  inasmuch  as  the 
bilge  is  the  connecting  link  between  the 
vertical  and  the  horizontal  plane,  that 
it  requires  a  greater  degree  of  strength 
than  other  parts  of  the  ship,  whereas 
it  has  less.  A  variety  of  means  have 
been  proposed,  some  of  which  have 
been  adopted,  but  up  to  the  present 
time  nothing  has  been  presented  that 
will  so  effectually  remedy  the  evil,  as 
that  of  an  equalized  gradation  of  the 
butts  throughout  tin;  ship,  and  increas- 
ing the  siding  size  of  the  timbers  of 


MARINE  AND  NAVAL  ARCHITECTURE 


i'19 


the  bilge;  but  even  with  this  additional 
strength  the  bilge  strakes  should  be 
heavier  than  other  parts  of  the  ceil- 
ing. 

It  must  appear  evident,  that  a  pro- 
per gradation  of  butts  can  only  be  ob- 
tained from  the  expansion  plan,  and 
the  question  at  once  arises,  how  shall 
this  be  obtained,  inasmuch  as  every 
Naval  Architect  has  thus  far  failed  in 
obtaining  the  actual  shape  of  the  ves- 
sel in  her  expanded  state  ?  Although 
more  than  a  single  effort  has  been  made, 
the  reason,  and  doubtless  the  only  rea- 
son, why  European  Architects  have 
failed  to  accomplish  their  purpose,  is 
attributable  to  their  ignorance  of  the 
model.  It  is  this  alone  that  can  fur- 
nish two  curves  in  the  same  line,  and 
exhibit  both  at  the  same  time. 

It  willappear  obvious, that  an  expand- 
ed ship,  bounded  by  a  curved  line  both 
below  and  above,  must  have  a  straight 
line  somewhere,  and  that  this  straight 
line  would  be  the  proper  starting  point 
wherever  found;  as  all  parts  would 
commence  expanding  from  this  line,  it 
is  also  evident  that  this  line  is  precisely 
the  same  one  way  when  expanded  that 
it  was  when  in  its  rotundity ;  hence  we 
infer  that  it  will  furnish  correct  data 
for  the  extension  of  all  parts.      We  have 


' 


shown  the  line  in  Plate  2  in  the  sheer- 


plan,  and   in   one  section   of  the  hall- 
breadth  plan,  and    it  may  be  obtained 


in  the  following  manner  from  the  mo- 
del: plane  up  two  battens  thin  enough 
to  bend  around  the  model  longitudi- 
nally anywhere,  and  as  wide  a,s  :i  good 
rule-staff  should  be  by  the  scale  upon 
which  the  model  is  made,  say  S  or  10 
inches;  both  edges  being  perfectly 
straight,  apply  one  around  the  model 
at  the  upper  part  of  the  bilge  in  the 
direction  a  diagonal  line  usually  runs  ; 
apply  it  fair,  without  an  inclination 
either  up  or  down  ;  having  secured  it, 
apply  the  second  with  its  lower  vA>j;(> 
at  the  upper  edge  of  the  first,  as  near 
as  may  be  without  its  coaking  off  from 
the  bottom,  or  having  any  set  edgewise; 
they  may  not  seam  at  their  first  posi- 
tion, as  indeed  it  is  not  likely  that  they 
will.  We  shall  be  able,  however,  to 
determine  in  which  direction  they  are 
required  to  move,  in  order  to  secure  a 
seam  or  a  joint  of  the  two  edges ;  by 
thus  moving  them  we  shall  rind  a  po- 
sition in  which  they  will  form  a  joint 
of  their  edges,  and  at  the  same  time  tit 
the  bottom  or  side  of  the  model ;  when 
that  plane  is  found,  we  have;  the  base 
of  the  expansion  plan,  viz.,  a  straight 
line.  It  is  true,  that  all  Architects  ex- 
pand from  a  straight  line:  hut  they 
take  it  for  granted,  that  because  the 
base  is  a  straight  line  in  its  rotundity, 
it  must  of  necessity  he  on  a  plane. 
We  find  the  straight  base,  and  from  its 
proper    location,    project    the    design: 


220 


M\IMNK    AND    NAVAL    ARCHITECTURE 


hence  the  difference  lies  just  hen — 
they  place  the  base  at  the  edge  of  the 
design,  we  near  the  centre.  Having 
marked  the  upper  edge  of  the  lower 
staff,  or  the  lower  edge  of  the  upper 
one,  we  may  mark  the  exact  station  of 
every  frame  on  the  edge  of  the  staff, 
(their  stations  having  previously  been 
marked  across  the  outside  ofthe  model.) 
In  applying  those  stations  to  llie  draft, 
it  will  be  discovered,  that  the  dead-Hat 
frame  must  be  squared  from  the  straight 
line,  inasmuch  as  every  other  will  vary 
more  or  less  from  square  as  the  frame 
is  more  or  less  distant  frOm  this  frame. 
We  may  now  girl  the  O  frame  in  the 
body-plan,  by  applying  a  batten,  and 
marking  every  water-line  below  and 
above;  also  ihe  sheer-lines.  The 
rail  being  the  upper  boundary,  and  the 
base  or  side-line  the  lower  boundary 
line,  the  girt  of  every  fourth  frame  may 
be  obtained  in  the  same  manner;  the 
spots  should  be  marked  parallel  to  the 
base  of  expansion,  for  the  following 
reasons  :  when  we  have  spoiled  all  the 
lines  on  every  fourth  frame,  we  may 
apply  a  batten  to  each  water  and  sheer- 
line  in  the  hall-breadth  plan,  marking 
the  station  of  all  the  fourth  frames  on 
the  batten  while  thus  bent  ;  we  may 
then  apply  the  batten  to  the  expansion 
plan,  keeping  the  dead-flat  spot  on  the 
batten  at  the  line  representing  that 
frame.      All   the    marks   on  the   batten 


may  now  be  brought  to  intersecl  the 
girth  spots,  and  the  crossing  will  be 
the  correct  spot  for  the  expanded  line 
on  the;  frame  it  represents.  The  ex- 
panded shape  of  every  line  may  be  ob- 
tained in  the  same  manner  ;  and  all 
the  frames  may  also  be  marked,  and 
will  be  required  to  complete  the  plan. 
The  endings  of  every  line  will  also  be 
necessary,  and  may  be  swept  by  the 
spots  at  both  ends  of  the  plan.  We 
shall  find  that  the  ends  aft  form  a  cu- 
rious line;  and  in  order  to  complete 
the  plan,  we  may  find  it  necessary  to 
run  in  one  or  more  lines  in  the  buttock 
after  the  lines  are  all  swept  in,  the 
sheer-lines  with  ink  (and  all  the  water- 
lines  with  pencil  which  are  not  re- 
quired) after  tin;  frames  are  regulated 
and  swept  in  with  ink  also.  We  may 
remove  the  water-lines  with  India  rub- 
ber, and  proceed  first  to  tin?  arrange- 
ment of  tin;  butts  of  the  frame,  having 
the  whole  side  of  the  ship  before  us — 
the  lower  edge  of  the  draft  being  the 
side  of  the  keel,  and  its  upper  edge  the 
rail.  It  may  now  be  plainly  discovered 
that  the  floors  should  be  the  starting 
point,  and  that  if  we  determine  the 
length  ofthe  floor  to  be  invariable,  we 
return  to  the  present  system:  but  sup- 
pose we  determine  to  have  5  feet  scarf 
to  the  frame,  or  5  feet  from  one  butt  on 
the  frame  to  the  next  above  or  below, 
and  that  e\er\   fifth  frame  shall  be  the 


MARINE    AND    NAVAL    ARCHITECTURE. 


221 


usual  length,  or  say  midships  10  feet, 
arm  and  cut  by  a  hue  running  as  the 
diagonal  showing  floor  head  runs  in 
Plate  9;  and  suppose  0,E,  K,  and  so  on 
were  cut  to  this  line:  A,  15  inches 
below  ;  B,  30  inches  below  ;  C,  45 
inches  ;  D,  60  inches,  or  5  feet  below  ; 
E  will  come  to  the  diagonal.  Now  D 
being  60  inches,  or  5  feet  shorter  on 
one  side,  may  be  5  feet  longer  on  the 
other  side  of  the  ship,  and  it  will  be 
readily  perceived  that  the  floors  are 
easier  obtained  ;  it  will  also  be  discov- 
ered that  the  second  futtocks  would 
follow  the  same  arrangement,  and  would 
not  be  .confined  to  a  certain  shape  as 
they  now  are.  The  fourth  futtock 
would  also  follow  in  like  manner,  and 
with  like  advantages  ;  so  of  the  top- 
timber  or  half  top-timber  ;  but  we  see 
no  reasons  why  this  arrangement  should 
be  confined  exclusively  to  the  floor 
head.  The  first  futtocks  may  be  ad- 
justed in  the  same  manner,  (and  with 
this  exception)  the  dead-flat  may  be 
framed  as  they  now  are  ;  that  frame  or 
any  other  frame  should  not  butt  on  the 
keel,  for  the  following  reason — the  large 
bulk  of  timber  in  vertical  line  over  the 
throats  of  the  floors,  in  addition  to  the 
keel  below,  requires  more  fastening 
surface  than  is  obtained  from  the  pres- 
ent mode  of  construction.  By  extend- 
ing the  Hist  futtock  to  the  side  of  the 
keel,  we   virtually  make  a  floor  timber 


of  every  timber  that  has  a  landing  or  a 
place  on  the  keel.  This  would  he  as 
it  should,  and  every  ship  that  gets 
ashore  and  loses  her  keel,  more  firmly 
establishes  the  truth  of  our  statement ; 
and  we  will  add,  that  any  mechanic 
may  but  examine  the  socket  or  seat 
from  whence  a  keel  has  been  taken, 
and  we  are  persuaded  that  he  will  think 
as  we  do  in  this  particular.  By  ex- 
tending every  first  futtock  across  the 
keel,  we  not  oidy  distribute  the  fasten- 
ing, which  adds  to  tin;  strength  of  the 
floors,  but  make  a  floor  of  the  fust 
futtocks ;  by  this  arrangement  the 
length  of  the  first  futtock  is  increased 
7  or  8  inches  on  the  keel  alternately, 
first  from  one  side  and  next  from  the 
opposite  side.  The  head  of  the  first 
futtock  may  have  the  same  length  of 
scarf  as  before,  above  the  floor  head.  ;is 
determined  upon  below,  viz.,  5  feel  ; 
and  as  we  shortened  the  floor  of  frame 
A  15  inches,  we  likewise  shorten  the 
first  futtock  15  inches  on  A ;  30  on  l> : 
45  on  C  ;  and  60  on  D.  It  m;i\  he  ar- 
gued that  this  arrangement  makes  a 
shorter  first  futtock;  to  this  objection 
we  say  that  it  is  so,  but  on  one  side 
only  at  the  same  time ;  and  though  tin; 
first  futtocks  may  be  shorter  than  they 
usually  are,  it  matters  not  ;  lor  while 
we  are  dispensing  with  some  of  the 
surplus  strength  between  the  keel  and 
first   futtock-heads,  we  do  so   in   order 


222 


MARINE    AND    NAVAL    ARCHITECTURE. 


to  add  the  amount  thus  taken  to  the 
bilge,  which   requires  even   more  than 
other  parts   of  the   ship  to  render  that 
part  equally  secure  with  other  parts  of 
the  hull. 

It  is  a  difficult  matter  to  convince 
the  casual  observer  that  all  parts  of  the 
ship  should  be  equally  strong,  or  have 
strength  in  proportion  to  the  stress  that 
each  part  maintains,  else  rupture  to 
some  extent  is  likely  to  ensue  ;   but  the 


new,  lest  it  should  cost  something; 
hence,  as  we  have  had  occasion  to  re- 
mark, almost  every  improvement  is  op- 
posed but  that  of  price  for  building, 
and  the  owner  is  not  less  al  fault  :  the 
cheapest  is  the  best  with  him:  so  long 
as  his  ship  will  insure  for  A  No.  1  lit- 
is satisfied,  (if  we  may  be  allowed  to 
judge  from  his  acts;)  he  had  rather 
spend  5000  dollars  in  extra  exterior 
show  to  attract  and  dazzle  the  eyes  of 


gradation  of  butts  extends  to  the  second  passengers,  than  to  spend  half  the 
futtocks  in  like  manner,  and  furnishes 
the  moulder  with  an  opportunity '  of 
moulding  timber  that  could  scarcely  be 
worked  into  the  frame  but  for  this  im- 
provement. The  like  may  be  said  of 
the  third  and  fourth  futtocks  ;  and  the 
extension  of  this  systematic  mode  of 
distribution  is  not  prejudicial  to  any 
part  of  the  entire  frame  ;  and  while  we 
repeat  that  it  will  furnish  a  new  mode 
of  security  to  the  ship  with  the  same 
weight  of  materials,  and  the  same  if  not 
less  cost,  also  that  we  would  be  less 
dependent  upon  certain  crooks  for  par- 
ticular limbers,  than  at  present.  But 
this  is  not  all:  there  is  no  timber  (as  far 
as  shape  is  concerned)  but  would  work 
into  a  ship's  frame.  But  it  may  be 
asked,  why  has  not  this  been  discovered 
before  ?  we  say  because  vessels  have 
not  been  expanded  is  the  reason  ;  and 
the  second  reason  may  be  found  in  the 
fact,  that  builders   repudiate  any  thing 


noiint  in  obtaining  an  extraordinary 
strong  ship,  and  in  the  end  the  cheap- 
est. But  again,  those  two  are  not  the 
only  parties  at  fault;  the  underwriters 
are  censurable  to  some  extent  in  not 
selecting  men  to  superintend  their  in- 
terest in  these  matters,  who  are  .me- 
chanics of  the  first  grade.  Sea  cap- 
tains are  not  the  most  suitable  men  to 
superintend  the  construction  of  a  ship, 
(themselves  to  the  contrary  notwith- 
standing,) however  well  qualified  for  the 
spars,  rigging,  and  outfits ;  and  we 
think  we  are  right  in  this  matter  when 
we  say  the  insurers  have  been  the 
losers  in  consequence  of  this  arranger 
ment.  But  Ave  have  said  that  this 
method  will  cost  no  more  than  the 
present  arrangement  of  the  butts; 
the  making  of  the  moulds  of  a  ship 
would  perhaps  require  from  2  to  3 
days'  work  more  ;  the  moulder  would 
at    first    be    compelled    to  move  more 


MARINE    AND    NAVAL    ARCHITECTURE. 


223 


cautiously;  but  working  out  the  frames 
and  putting  them  together  it  is  quite 
evident  would  cost  no  more;  as  to  the 
raising  and  regulating  of  which,  we 
shall  treat  in  its  proper  place.  They 
will  cost  no  more,  we  are  quite  well 
persuaded  ;  but  all  that  has  been  spent 
by  the  builder  in  the  loft,  and  the  time 
of  the  moulder,  will  be  amply  repaid  in 
the  facility  of  obtaining  timber  to  suit 
his  moulds.  We  have  been  consider- 
ing the  relative  value  in  dollars  and 
cents,  but  gold  dwindles  into  insignifi- 
cance when  the  better  security  of  hu- 
man life  is  to  be  the  result. 

Our  readers  will  readily  be  able  to 
conceive  the  advantages  of  this  ar- 
rangement of  the  butts,  if  they  will 
compare  the  present  manner  of  ar- 
ranging the  butts  of  the  outside  plank. 
Let  alternately  every  other  strake  butt 
upon  the  same  frame  from  the  floor 
heads  to  the  rail,  and  there  will  be  no 
difficulty  in  settling  the  question  at 
once,  that  much  of  the  strength  of  the 
present  arrangement  would  be  lost. 
The  advantages  are  apparent,  when 
we  consider  that  the  system  makes  no 
requisition  on  the  room  for  stowage ; 
unlike  the  English  system  of  riders, 
that  made  such  heavy  drafts  on  the 
room  for  cargo,  it  is  presented  to  the 
world  depending  on  its  own  merits. 
But  the  expansion  plan  stops  not  here: 
having  adjusted  the  butts  of  the  frame, 


we  may  now  proceed  to  divide  tin1  en- 
tire surface  into  strakes  of  proper 
width;  the  sheer-lines  will  furnish  data 
above,  and  we  must  not  depart  from 
them,  inasmuch  as  they  furnish  the 
actual  shape  edgewise  of  the  plank  or 
strakes,  that  shows  the  sheer;  retain- 
ing the  form,  we  may  make  such  divi- 
sions of  width  as  we  please.  The  bot- 
tom may  also  be  divided  into  strakes: 
remembering  that  although  there  is  no 
difficulty  in  bending  lie  batten  on  the 
paper  to  any  division  we  may  make, 
yet  it  is  vastly  important  that  we  so 
divide  the  bottom  that  the  plank  may 
be  obtained  as  near  the  required  shape 
as  may  be,  and  at  the  same  time  work 
on  the  ship  easily  ;  and  although  the 
young  beginner  would  perhaps  hesitate 
to  take  the  responsibility  of  lining  the 
plank  of  a  ship,  he  has  now  an  oppor- 
tunity not  only  of  planking  a  ship,  hut 
if  he  goes  wrong,  he  may  recover  his 
lost  ground  without  damage,  inasmuch 
as  he  may  make  all  his  marks  below 
the  wale  with  pencil,  until  he  is  satisfied 
that  he  i^  right,  and  then  he  can  mark 
them  in  with  ink.  There  arc  several 
important  things  that  must  not  he  for- 
gotten in  arranging  the  strakes ;  we 
must  remember  that  the  smallest  girth 
presented  is  perhaps  some  20  to  W  feel 
forward  of  the  stern-post,  and  the 
largest  space  to  be  covered  is  on  the 
post   and    cross-seam.     Hence  it   will 


224 


M  VRIXE    AND    NAVAL    ARCHITECTURE. 


appear  obvious  that  the  plank  should  be 
narrow  on  the  Conner  and  wide  on  the 
latter  part.  But  again;  plank  should 
not  be  wide  above  water,  and  to  re- 
move the  difficulty,  we  may  butt  two 
after-woods  to  a  midship  plank,  which 
will  enable  us  to  get  up  on  the  stern- 
post,  and  even  on  the  transom,  with 
the  after-woods,  while  the  butts  of  the 
midship  plank  will  be  below  water. 
Indeed  the  opening  should  be  less  if 
possible  immediately  on  coming  on  the 
transom  than  it  is  10  or  20  feet  for- 
ward, else  the  plank  will  be  widest  on 
the  after  end,  which  will  appear  dis- 
pr< (portioned,  inasmuch  as  the  wales 
are  tapered,  or  are  narrower  on  the 
after  end  than  farther  forward  ;  and, 
as  a  consequence,  other  strakes  should 
correspond,  or  the  discrepancy  is  at 
once  apparent ;  not  only  so,  but  to  look 
well,  the  wood  ends  on  the  cross-seam 
should  measure  less  on  the  bevel  of  the 
butt  than  they  do  farther  forward  on 
the  square,  else  they  will  appear  to  be 
the  wrong  end  aft ;  not  only  so,  but 
the  sni  will  be  a  derangement  in  the 
appearance  ;  the  upper  edge  of  the 
after-woods  on  the  transom  should  not 
be  round,  else  the  buttock  will  want 
the  appearance  of  symmetry,  inasmuch 
as  the  strakes  coming  from  below  have 
a  hollow  upper  edge,  and  the  strakes 
above  should  also  be  hollow  ;  but  al- 
though it  may  be  entirely  lost  and  be- 


come straight,  it  should  not  be  round 
The  wood  ends  forward  on  the  steii 
differ  very  materially  both  in  the  re 
quired  width  and  shape.  First,  the 
opening  is  much  smaller  forward  than 
aft;  and  while  we  avoid  the  sni  aft  on 
the  upper  edge,  we  cannot  avoid  it  for- 
ward, although  it  may  be  reduced  very 
much.  The  upper  wale  has  a  very 
considerable  sni  or  round  on  the  upper 
edge  ;  this,  however,  is  diminished  as 
we  come  down,  and  the  manner  of  doing 
it  is,  by  making  the  forward  end  of  the 
wale  narrower.  This  method  of  put- 
ting on  the  wales  is  not  general  ;  in 
very  many  places  ships  are  built  (in 
this  particular)  as  of  old,  with  the  wale 
as  wide  at  each  end  of  the  ship  as  in 
the  centre.  A  tapered  wale  is  an  ad- 
vantage, not  only  in  appearance,  but  in 
reality,  inasmuch  as  the  less  we  bend 
the  plank  edgewise,  the  fewer  grains 
are  cut  off  in  working  out  the  plank 
to  the  shape  required,  and,  as  a  conse- 
quence, more  strength  is  retained  in 
the  plank  when  in  its  place  on  the  ship. 
There  is  a  deceptive  appearance  con- 
nected with  the  shape  of  the  plank  on 
the  bow  of  a  vessel  in  particular.  The 
eye  may  be  in  a  position  from  which 
the  shape  of  the  plank  edgewise  may 
appear  straight,  when  in  fact  the  plank 
in  40  feet  of  length  from  the  wood  ends 
may  have  from  3  to  4  feet  of  crook  ; 
that  is  to  say,  that  it  would  require  a 


MARINE  AND    NAVAL    ARCHITECTURE, 


225 


straight  plank  3  to  4  feet  wide  in  ad- 
dition to  the  width  of  the  plank  when 
finished,  to  furnish  the  actual  shape 
when  on  the  vessel.  The  casual  ob- 
server would  suppose  from  the  actual 
shape  shown  on  the  expansion  plan, 
that  there  must  be  some  mistake  about 
the  plan,  inasmuch  as  the  sheer  ap- 
pears to  be  nearly  straight.^  Many 
men  who  may  be  regarded  as  good 
mechanics  have  been  thus  deceived. 
This  crook  edgewise  is  what  is  usually 
termed  sni,  and  is  consequent  upon  the 
twist  of  the  plank,  and  the  higher  up 
on  the  bow  we  ascend,  the  more  we 
have  of  the  twist,  consequent  upon  the 
increased  flare ;  thus  the  philosophy 
will  at  once  appear  of  making  the  plank 
narrower  as  we  ascend  toward  the  rail, 
where  we  have  the  most  bend  edgewise, 
and  of  making  them  wider  as  we  de- 
scend, where  the  plank  can  be  worked 
out  to  their  actual  shape.  There  are 
many  ships  that  have  so  much  flare  to 
their  bow  immediately  under  the  rail, 
that  the  bulwarks  could  not  be  put  on 
smoothly  more  than  31  inches  wide,  the 
bend  edgewise  is  so  great.  This  will 
be  shown  by  the  expansion  plan — as 
we  descend,  the  twist  diminishes,  and, 
as  a  consequence,  the  sni  decreases. 
Hence  we  discover  that  it  is  not  only 
advantageous  to  the  ship,  but  to  the 
builder  and  the  men  who  plank  the 
ship,  (this  part  of  the  work  being  very 


generally  done  by  contract,)  to  avoid 
this  edge  crook  as  far  as  is  consistent 
with  the  shape  of  the  vessel ;  first,  be- 
cause the  ship  is  stronger;  second,  be- 
cause it  saves  plank;  and  thirdly,  be- 
cause it  saves  labor  in  putting  on  the 
plank — the  full  ship  has  more  of  the 
sni  than  one  having  less  buoyancy. 

It  will  perhaps  be  well  enough  to  line 
the  upper  edge  of  the  lower  strakes 
hollow,  else  before  we  are  aware  of  it 
wye  shall  have  the  edge  round,  in  con- 
sequence of  the  twist.  Were  we  to 
line  the  lower  edge  of  the  garboard 
strake  to  the  exact  spiling,  and  the 
upper  edge  straight,  we  shall  rind  that 
the  strake  above  would  require  to  be 
quite  hollow  on  the  lower  edge.  The 
secret  of  this  crook  or  sni  is  thus  de- 
fined— the  forward  end  of  the  plank  on 
the  stem  rises  perpendicularly  its  whole 
width  ;  the  bottom  may  be  supposed 
to  be  flat,  or  without  dead  rise  ;  the 
after  end  of  the  plank,  although  double 
the  width  of  the  forward  end,  does  not 
rise,  while  in  the  middle  of  the  length 
of  the  plank,  it  has  raised  more  than  a 
mean  between  the  two  ends  :  this,  with 
all  the  necessary  information  lor  plank- 
ing a  ship,  is  furnished  by  the  expan- 
sion plan.  True,  the  liner  requires 
judgment ;  for  example,  lie  should  make 
his  strakes  narrower  on  the  bilge  than 
on  the  Hat  of  the  bottom,  because  of 
the  loss  in  the   scantling    size  of  the 


29 


?2G 


MARINE    AND    NAVAL    ARCHITECTURE 


frame,    by    making  the   bilge  straight 
the  width  of  the  plunk. 

The  foregoing  remarks  will  doubt- 
less be  quite  siiffieient,  inasmuch  as 
the  plan  before  the  pupil  will  explain 
itself.  After  dividing  the  entire  plan 
into  st rakes,  we  may  arrange  the  butts  ; 
not,  however,  for  the  arbitrary  confine- 
ment of  the  butts  on  the  ship,  but  to 
familiarize  our  eye  with  the  best  ar- 
rangement ;  and  we  should  approxi- 
mate as  near  as  the  plank  will  allow, 
as  the  plank  sometimes  determines  for 
us  where  the  butt  shall  be.  We  are 
well  persuaded  that  the  apprentice 
could  spend  his  time  profitably  in  learn- 
ing to  draw  an  expansion  plan  of  a  ship, 
and  we  would  scarce  hesitate  to  say, 
that  the  mechanic  would  find  it  to  his 
advantage  to  improve  in  that  of  which 
he  knew  but  little  about,  on  this  ex- 
panded plane; few  men  could  be  per- 
suaded of  the  actual  form  of  a  ship 
spread  out  in  this  manner.  It  does 
not  necessarily  follow  that  the  straight 
line  for  expansion  should  be  straight  in 
the  body-plan  unless  straight  on  the 
plane.  In  Section  4  of  Plate  2  we 
have  shown  the  expansion  base-line  to 
be  a  curved  line  ;  and  it  would  have 
been  difficult  to  understand  why  this 
should  be  so,  inasmuch  as  the  base  is 
straight,  and  runs  near  the  same  direc- 
tion as  the  ordinary  diagonal,  which  is 
always  straight  in  the  body-plan.     But 


however  paradoxical  it  may  appear,  it 
is  nevertheless  true,  that  this  line  may 
not  be  straight  in  the  bodv-plan,  or  on 
the  plane  expanded. 

It  will  be  remembered  that  we  have 
shown  the  smallest  girth  to  be  from  20 
to  30  feet  forward  of  the  post.  This 
would  seem  to  have  a  depressing  influ- 
ence oil  the  base  in  the  body-plan. 
Again,  the  largest  girth  is  found  at  the 
post,  which  tends  to  elevate  the  line  in 
the  body- plan.  The  fore-body  like- 
wise has  some  peculiarities ;  we  dis- 
cover the  line  starting  at  the  same  al- 
titude on  the  ®  frame  of  the  fore-body, 
and  the  frames  shortening  faster  than 
they  do  aft,  the  line  is  somewhat  de- 
pressed for  a  time;  at  length  the  Hare 
of  the  bow  causes  an  elevation  in  the 
upper  boundary  line,  and  when  we 
reach  the  side-line  on  the  stem  we  find 
a  much  shorter  girth,  and,  consequent- 
ly, a  depressed  ending.  Thus  we  see, 
that  buoyancy  concentrated  in  any 
part  of  the  ship  may  have  an  influence, 
and  this  is  as  it  should  be.  When  this 
departure  from  the  straight  line  takes 
place  in  the  body-plan,  and,  as  a  conse- 
quence, in  the  expansion  plan,  it  shows 
that  the  line  from  which  we  expand 
the  vessel  was  not  a  perfectly  straight 
line  in  the  direction  in  which  it  was 
taken.  This  is  the  case  with  Section 
4  of  Plate  2  ;  the  line  was  swept  on 
the  model  by  the  edge  of  the  rule  stall', 


MARINE    AND    NAVAL    ARCHITECTURE. 


227 


and  without  reference  to  its  being  ex- 
actly straight,  being  only  particular  to 
obtain  a  true  spiling.  Hence  it  was 
only  necessary  to  determine  the  ex- 
tent of  the  curve;  and  this  obtained  the 
base  of  expansion  was  furnished.  But 
the  method  already  shown  of  obtaining 
this  base  by  two  staffs  is  preferable  to 
that  of  using  one  staff  first  from  above 
and  next  from  below. 

The  expansion  plan  will  not  only  be 
found  useful  as  an  auxiliary  in  the  dis- 
tribution of  the  material  for  strength  ; 
but  we  may  be  able  more  readily  to  de- 
termine the  surface  for  the  purchase 
of  copper  or  sheathing,  which  is  not 
unworthy  of  notice.  Having  furnish- 
ed all  the  information  necessary  to  pro- 
ject an  expansion  plan,  or  to  spread  a 
ship  out  on  a  plane,  we  shall  next  en- 
deavor to  show  the  method  of  enlarg- 
ing and  contracting  models,  that  is  to 
say :  if  the  model  or  form  pleases  us, 
in  what  manner  or  how  shall  we  en- 
large or  reduce  the  vessel,  and  yet  re- 
tain the  same  shape  through  a  system 
of  proportions?  This  knowledge  will 
often  be  found  useful  to  such  as  would 
imitate  the  form  delineated  in  a  larger 
or  smaller  vessel;  the  principle  upon 
which  size  accommodates  shape  is 
strictly  proportional,  and  is  founded  on 
the  principles  of  similar  triangles  ;  it  is 
a  source  of  inconvenience  to  those  who 
would  increase  or  diminish  the  size  of 


a  vessel  from  that  set  forth  on  the  draft 
or  model,  inasmuch  as  an  alteration  of 
the  scale,  unless  strictly  proportional, 
is  an  equivalent  to  a  departure  from 
the  shape.  For  example,  we  double 
the  scale,  and  the  result  is,  that  the 
vessel  is  eight  times  as  large  ;  so  that 
it  will  be  readily  discovered,  that  if  we 
would  double  the  size  of  the  vessel,  we 
must  not  resort  to  this  means  of  en- 
larging ;  neither  will  it  answer  our  pur- 
pose to  decrease  the  size  of  the  vessel 
in  the  same  manner.  If  a  vessel  half 
the  size  of  another  is  required,  it  is  not 
enough  that  we  re-number  the  scale  by 
regarding  that  as  1  foot  which  was  be- 
fore  regarded  as  2  feet;  this  again  would 
make  the  vessel  but  one-eighth  of  the 
size.  Hence  it  must  be  quite  apparent 
to  the  discerning  mind,  that  if  we  would 
increase  or  diminish, whether  in  a  great- 
er or  less  degree,  we  musl  adopt  some 
system  that  can  be  relied  on  for  all 
sizes,  be  the  enlargement  or  the  con- 
traction what  it  may.  It  should  be  ap- 
plicable,, indeed  equally  so,  to  the  spars, 
or  any  and  every  part  of  the  vessel,  or 
any  other  structure.  It  is  as  we  have 
shown,  the  key-stone  of  mechanism — 
Nature's  Vatic  Mecum.  It  is  to  the 
mechanic  a  universal  dissolvent.  Va- 
rious methods  have  been  given  the  me- 
chanical world  for  increasing  or  re- 
ducing in  exact  proportion  every  part 
of  a  body  or  of  a  ship;   but  the  exam- 


228 


MARINE    AND    NAVAL    ARCHITECTURE 


pie  we  have  furnished  in  Plate  13, 
seems  to  us  to  be  the  one  best  adapted 
to  the  wants,  or  to  the  orbitual  career 
of  this  branch  of  the  mechanical  world, 
which,  while  it  is  correct,  it  is  easy  of 
application,  when  the  draft  of  a  ves- 
sel is  to  be  enlarged  or  reduced  as  a 
draft,  only  the  process  is  entirely  dif- 
ferent from  that  of  enlargement  or  re- 
duction of  the  same  for  building  pur- 
poses. For  example,  if  a  draft  is  drawn 
upon  a  scale  known  as  an  eighth  of  the 
inch,  and  we  wish  to  draw  another  or 
copy  that  draft,  we  find  it  necessary  to 
have  two  scales — the  one  correspond- 
ing with,  or  by  which  the  first  draft 
was  drawn,  the  other  corresponding 
with  that  to  be  drawn — and  by  mea- 
suring distances  on  the  small  draft  with 
the  small  scale,  and  applying  the  same 
to  the  large  draft  with  the  large  scale, 
we  may  increase  the  draft  to  any  size 
we  please ;  but  this  has  not  increased 
the  size  of  the  vessel  if  built  by  the 
draft ;  and  we  may  build  a  vessel  by 
each  draft,  and  they  would  both  be  of 
the  same  size,  although  one  draft  might 
be  double  the  size  of  the  other.  When 
the  vessel  itself  is  to  be  enlarged  or  re- 
duced from  the  same  model,  it  is  neces- 
sary to  find  the  exact  relation  in  the 
example  that  the  length,  breadth,  and 
depth  bear  to  each  other,  and  at  which 
they  are  to  be  brought  out ;  or  we  may, 
instead  of  taking  the  whole  depth,  take 


the  altitude  of  the  load-line  of  flotation 
above  the  base-line;  and  it  may  not  be 
out  of  place  hereto  remark,  that  in  all 
measurements  of  heights  taken  in  this 
country,  where  the  point  from  which 
we  measure  is  not  specified,  either  the 
load-line,  or  the  top  of  the  keel,  which 
is  usually  denominated  base-line,  should 
be  understood. 

In  England,  and  in  most  parts  of 
Europe,  the  lower  side  of  the  rabbet  is 
the  starting  point — a  most  inappro- 
priate place  for  imparting  instruction 
to  pupils.  Having  once  determined 
the  relations  of  length,  breadth,  and 
depth  to  each  other,  and  at  which  they 
are  to  be  brought  out  if  to  be  enlarged, 
we  may  find  the  length  of  tlje  model 
by  the  scale  upon  which  it  was  made, 
likewise  its  breadth  and  depth  by  the 
same  scale.  We  will  now  suppose 
the  ship  by  the  model  and  scale  to  be 
160  feet  long,  37  feet  beam,  and  20 
feet  deep ;  the  load-line  being  15  feet 
above  base  line,  we  want  to  enlarge 
the  ship  to  ISO  feet  long,  and  yet  re- 
tain the  identical  shape  after  being  en- 
larged, that  we  had  before  ;  we  will 
first  determine  the  principal  dimen- 
sions by  figures,  not  because  it  is  ac- 
tually necessary  to  pursue  this  course, 
but  because  it  will  doubtless  be  made 
more  clear  by  analogizing  the  two 
modes.  We  have  the  formula  in  the 
following  shape: — 


mini 


S$Sfl 


9  .*./  z 


?". 


I  2,vf   •• 


MARINE    AND    NAVAL    ARCHITECTURE 


229 


length      beura         length         beam 

160  :    37  :  :    ISO  :   41.63 


Again — 


length     depth         length        depth 

161)     20  :  :    ISO  :    22.5 

Again  we  have  for  the  altitude  of  the 
load-line — 

length       feet  0    length  feet 

160  :    15   ::    180  :   16.88 

The  result  is,  that  the  ship  of  160  feet 
long,  37  feet  beam,  and  20  feet  hold, 
is  enlarged  by  this  increase  to  180  feet 
long,  41  feet  7^  inches  wide,  and  22 
feet  6  inches  hold,  the  load-line  16  feet 
I0g  inches  above  the  base-line.  Thus 
we  discover,  that  though  the  principal 
dimensions  were  increased  scarcely  12 
per  cent.,  the  actual  tonnage  has  gained 
30  per  cent.,  for  we  discover  the  ton- 
nage by  the  former  dimensions  to  be 
1246  tons,  while  that  of  the  increased 
dimensions  amounts  to  1774  tons.  Al- 
though this  method  of  enlarging  and 
reducing  bodies  is  in  consonance  with 
the  principles  of  geometry,  yet  it  would 
be  a  tedious  and  almost  discouraging 
task  to  reduce  or  enlarge  a  ship  by 
calculations.  We  shall  present  another 
mode,  as  shown  in  Plate  13,  as  adapt- 
ing itself  not  only  to  ships,  but  to  all 
descriptions  of  vessels.  Assuming  a  A 
the  length  of  a  ship  to  be  enlarged ; 
a  b  will  also  be  assumed  to  be  the 
breadth,  and  a  c  the  depth  of  the  same 
vessel ;  we  will  next  assume  a  d  to  be 
the  length  required  ;  we  now  want  the 
proportions  that  will  furnish  the  pro- 
portionate size  and  shape  ;  and  in  order 


to  prove  our  former  expositions,  we 
will  assume  the  same  principal  dimen- 
sions as  before,  viz.:  160x37x20  feet 
deep  ;  let  the  distance  between  a  A  be 
160  feet,  and  the  distance  between  a 
b  37  feet ;  likewise  the  distance  be- 
tween a  c  20  feet,  and  the  distance 
between  a  d  180  feet,  the  required 
length.  We  thus  perceive  that  a  is 
the  stern  of  the  ship  in  both  cases  ;  the 
ship  turning  on  this  point,  A  is  the 
bow  of  the  ship  before  enlarged,  and  d 
afterward,  b  being  distant  from  «,  the 
breadth  of  the  vessel  must  of  necessity 
be  37  feet  distant ;  so  with  c,  that  hav- 
ing a  locality  of  20  feet,  the  depth  of 
hold  from  a  represents  the  depth. 

We  will  now  suppose  the  scale  by 
which  the  draft  or  model  to  be  en- 
larged is  designed  to  be  the  one-six- 
teenth of  an  inch;  then  we  have,  as 
in  Plate  13,  the  length,  breadth  and 
depth  shown  upon  this  scale  ;  from  A 
drop  a  line  square  from  the  first,  far 
enough  to  meet  another  line  running 
direct  from  a,  distant  from  a  ISO  feet, 
which  by  the  same  scale  is  the  distance 
required,  or  the  length  desired  ;  let  a 
second  and  third  line  be  dropped  from 
b  the  breadth,  and  c  the  depth,  far 
enough  to  intersect  the  line  last  drawn, 
the  result  will  be  that  we  are  furnished 
with  the  new  breadth  in  e,  and  the  new 
depth  in  /,  which  gives  the  same 
breadth  and  depth  as  before,  viz.:   e  41 


230 


MARINE    AND    NAVAL    ARCHITECTURE. 


feet  7f,  f  22  feet  6  inches;  but  this 
docs  not  stop  here  ;  the  proportionate 
breadth  and  depth  of  any  line  on  the 
ship  may  be  determined.  We  should 
not,  however,  forget  that  this  scale  is 
applicable  only  to  lengths,  breadths,  or 
depths;  it  does  not  apply  to  angular 
lines  ;  if  angular  lines  are  required,  let 
them  be  taken  from  the  plan  after  en- 
larged, or  let  the  angle  be  given,  and 
then  strike  a  line  in  the  projected  plan 
below  the  base  of  enlargement  at  a 
corresponding  angle  if  within  90  de- 
grees, if  without  90  degrees  angular 
measurements  will  not  be  required; 
and  indeed  they  cannot  facilitate  the 
work  to  any  considerable  extent,  inas- 
much as  the  half  or  whole  breadth 
may  be  applied  from  the  tables  of  the 
model  to  the  scale  base  of  the  160  feet 
ship  ;  the  breadth  or  half-breadth  being 
known,  square  the  spot  down  to  the 
scale  below  of  the  180  feet  ship,  and 
we  have  .all  we  want.  The  mode  is 
simple  in  principle,  and  ready  in  prac- 
tice, and  can  be  applied  by  any  me- 
chanic who  can  form  a  triangle  oil  a 
sheet  of  drawing  paper  margined  with 
a  scale  on  two  sides  ;  a  piece  of  veneer- 
ing formed  into  a  triangle  square  will 
be  found  useful  in  squaring  down  the 
breadths  from  one  scale  to  the  other. 
It  will  be  perceived  that  the  same  re- 
lation is  sustained  throughout.  We 
take  all  measurements  first  on  the  up- 


per scale,  and  squaring  them  down   to 
the  other  scale  we  have  the  proportion- 
ate enlargement,  whether  the  measure 
ment  be  length,  breadth,  or  height. 

We  have  said  that  this  method  for 
enlarging  the  draft  %ill  apply  equally 
to  contract  the  draft  or  model  to  small- 
er proportionate  dimensions,  which  we 
will  now  endeavor  to  demonstrate. 
We  have  seen,  that  by  squaring  the 
length  down  at  the  bow,  while  the  stern 
stood  fast,  we  increased  the  size  as 
we  descended  in  a  continued  ratio. 
Let  us  reverse  the  lines,  and  assume 
the  lower  line  to  be  the  shortest,  which 
it  undoubtedly  would  be,  if  we  squared 
from  below.  Hence  it  will  appear 
manifest,  that  if  we  wished  to  reduce 
the  ship  from  ISO  feet  long  to  160  feet 
long,  it  would  only  be  necessary  to  form 
an  angle  of  90  degrees  below,  one  line 
intersecting  the  upper  line  in  a,  and 
the  other  in  A,  the  90  degrees  being 
only  another  name  for  a  square  ;  and 
this  theorem  is  equally  true  of  any 
other  dimensions  we  may  wish  con- 
tracted or  expanded;  and  in  the  ab- 
sence of  a  better  rule,  it  will  apply  to 
the  enlargement  or  contraction  of  the 
spars  of  a  ship,  as  we  shall  show  in  its 
proper  place. 

The  methods  used  in  England,  and 
indeed  other  parts  of  Europe,  arc,  in 
our  judgment,  less  simple,  but  founded 
upon  the  same  fundamental  principle" 


MARINE   AND    NAVAL    ARCHITECTURE. 


231 


of  similar  triangles.  That  our  readers 
may  be  able  to  judge  for  themselves  of 
the  feasibility  of  each,  we  will  exhibit 
one  method  shown  by  Mr.  Fincham, 
but  not  as  clearly  illustrated  as  it 
should  have  been,  and  will  endeavor  to 
make  up  the  deficiency  in  our  illustra- 
tion. 

First  find  the  relation  that  the  length, 
breadth  and  depth  bear  to  each  other 
exaetlv.      If  the  size  is  to  be  increased, 
as  in  Plate  14,  strike  in  the  load  water- 
line,  as   we  have    shown   on  page  43 
in  the   body-plan  ;    inasmuch    as    this 
method,  as  far  as  heights  and  breadths 
are  conjcerned,  is  derived  entirely  from 
the  body-plan,    the   fourth    frames    of 
which  will  be  quite  sufficient  to  furnish 
the  proportions  we  require.    This  is  not 
all,  however;   there    must  be   another 
plan  from  which  to  determine  the  pro- 
portionate  lengths,  and  this   plan  Mr. 
Fincham    has    given,    which    is    simi- 
lar to  that    already    given,   but    much 
less  clear.     Hence  it  will  be  seen  that 
our  only  expositions  will  refer  to  the 
body-plan.      We  first  assume  that  we 
have  the  fourth  frames  of  the  body-plan 
we  wish  to  enlarge  ;   we  have  also  the 
water-lines  stricken  across    the  plan ; 
we  next  carry  out  all  the  water  and  all 
the  sheer-lines,  or  their  heights,  on  each 
frame  ;   we  then  are  required  to  find  the 
third  line  of  the  triangle,  that  will  fur- 
nish the  height  we  require.     Suppose, 


for  example,  the  load-line  depth  above 
the  base  to  be  10  feet,  and  we  require 
12,  we  have  but  to  measure  12  feet 
(starting  from  the  point  where  a  per- 
pendicular from  the  breadth  at  the 
dead-flat  frame  crosses  the  base-line) 
in  the  angular  direction  to  load-line, 
that  is  to  say  :  open  the  dividers  to  12 
feet,  and  placing  the  first  leg  at  the 
point  shown,  and  swinging  the  other 
leg  from  the  perpendicular  direction  to 
the  angular,  until  it  meets  the  load-line, 
mark  the  spot,  and  then  draw  a  line 
from  the  point  shown  below  to  inter- 
sect this  point,  and  continue  up  until  it 
intersects  all  the  heights  leveled  out  ; 
thus  we  have  a  triangle  formed,  two 
sides  only  of  which  are  actual  measure- 
ments, viz.,  the  perpendicular  and  the 
angular;  the  level  lines  are  only  in- 
tended as  connections,  or  as  an  index 
to  refer  from  the  height  on  one  line  to 
its  corresponding  height  on  the  other. 
It  then  follows,  that  increased  heights 
are  found  on  this  angular  line,  and  ap- 
plied perpendicularly  ;  but  this  plan 
applies  to  heights  only  ;  another  trian- 
gle must  be  projected  for  the  breadths, 
and  is  bounded  by  the  middle-line  ;it 
the  base,  and  by  the  point  before  de- 
signated, viz.,  the  connection  of  the 
breadth-line  with  the  base,  and  by  the 
line  to  be  obtained;  at  the  intersect  ion 
of  the  frames  with  the  water-lines  drop 
perpendicular   lines,  that    is,   at  every 


232 


MARINE    AND    NAVAL    ARCHITECTURE 


crossing-  of  the  water-line  by  the  frame, 
lei  si  perpendicular  fall,  that  from  the 
dead-flat  on  load-line  will  be  but  a  con- 
tinuation of  the  half-breadth  line;  a 
line  now  extending  from  this  line  to 
the  middle-line  at  base,  and  correspond- 
ing in  length  with  the  breadth  we  re- 
quire, furnishes  the  angular  line  of  this 
triangle;  and  it  will  be  at  once  per- 
ceived, that  at  every  crossing  of  the 
base-line,  we  have  the  former  actual 
half-breadth  of  some  frame  on  a  given 
water-line,  and  the  angular  line  shows 
those  half-breadths  as  required,  which 
may  be  seen  by  referring  to  Plate  14. 
But  by  Mr.  Fincham's  rule  (if  we  should 
apply  the  well-known  adage,  viz.,  that 
it  is  a  poor  rule,)  it  icill  not  work 
both  ways. 

If  we  wish  to  reduce  the  size  or  the 
dimensions  of  a  vessel,  we  must  pur- 
sue a  different  course  from  that  shown 
in  the  rule  for  enlarging.  The  water- 
lines  are  carried  no  farther  out  than 
the  half-breadth  line,  from  which  line 
they  shape  a  different  course ;  so  also 
with  their  crossing  the  frames ;  those 
points  at  which  they  cross  extend  in 
one  direction  no  farther  than  the  base- 
line. In  the  case  of  enlargement,  the 
heights  were  shown  to  be  at  right  an- 
gles with  the  half-breadth  perpendicu- 
lar, not  only  at  the  sheer,  but  at  the 
water-lines.  So  also  with  the  halt- 
breadths  ;   they  were  shown  to  be  in 


their  extension  below  the  base-line  at 
right  angles  with  that  line  :  in  this 
case,  the  right-angled  corner  is  formed 
outward,  while  before  it  was  formed 
inward.  The  water-lines  are  carried 
across  the  body-plan,  and  no  farther  in 
a  direct  line;  the  intersections  of  the 
frames  with  the  water-lines  are  dropped 
no  lower  than  the  base-line.  Hence  it 
is  apparent,  that  the  half-breadth  line, 
and  the  base-line  forming  the  side  of  the 
triangle,  has  the  acute  angular  con- 
nection at  each  end,  while  each  of  the 
other  two  sides  of  the  triangles  connect 
with  each  other  at  one  termination  and 
form  right  angles,  and  at  the  other  con- 
nect with  the  half-breadth  and  base- 
lines respectively.  Hence  it  follows, 
that  we  have  only  to  find  the  proper 
relation  the  breadth  and  depth  bear  to 
each  other  ;  and  from  the  outboard  cor- 
ner of  the  body  half-breadth,  extend  the 
half-breadth  of  the  dead-flat  frame  an- 
gularly inward  ;  the  line  at  the  same 
time  forms  an  angle  of  90  degrees,  with 
another  line  running  in  the  direction  of 
and  terminating  at  the  connection  of 
the  middle  and  base-lines.  In  like 
manner  the  heights  of  water  and  sheer- 
lines  form  a  triangle  kind  of  scale  on 
the  outside,  or  halt-breadth  line.  In 
the  triangle  of  heights  a  parallel  line  is 
extended  from  the  half-breadth  line  to 
the  side  of  its  diminished  grade,  on 
which  all   the  actual  heights  may  be 


MARINE    AND    NAVAL    ARCHITECTURE 


233 


seen,  as  in  Plate  14.  So  also  with  the 
half-breadths;  they  take  theirdeparture 
from  the  base-line,  and  ran  parallel 
with  the  outer  side  of  the  triangle, 
meeting  the  half-breadth  side,  in  regu- 
lar order.  Thus  we  see  that  the  in- 
board side  of  the  lower  triangle  shows 
the  half-breadths,  and  the  lower  side  of 
the  upper  triangle  shows  the  several 
heights  respectively,  as  shown  in  Plate 
14.  The  diminished  length  is  obtained 
in  the  same  manner  as  we  have  shown 
in  our  own  expositions. 

The  reader  scarce  needs  a  single 
word  from  us  on  the  comparative  mer- 
its of  those  two  methods  of  enlarging 
and  reducing-  drafts  or  models,  retain- 
ing at  the  same  time  the  same  identi- 
cal shape.  If  the  first  method  we  have 
described  were  adopted,  we  would  not 
hesitate  to  make  the  alteration  on  the 
floor  of  the  mould-loft  after  the  vessel 
was  laid  down.  We,  however,  can 
scarcely  conceive  that  such  a  contin- 
gency would  occur,  unless  it  were  de- 
termined to  increase  or  diminish  the 
size  of  the  vessel  after  she  was  laid 
down.  We  say,  that  in  such  case  we 
would  not  hesitate  to  enlarge  or  reduce 
on  the  floor  in  the  manner  we  have  de- 
scribed, without  either  making  another 
model  or  drawing  a  draft.  We  are 
aware  that  vessels  are  often  altered 
from  the  model;  but  let  us  inquire 
how  ?     Are    they  altered   mathemati- 


cally, or  by  geometrical  rules,  in  the 
United  States?  that  is  to  say,  is  the 
identical  shape  retained,  notwithstand- 
ing the  vessel  is  enlarged  or  diminish- 
ed? Whatever  may  yet  be  done  in 
this  particular  in  this  country,  we  can 
only  say  that  this  has  not  yet  been  ac- 
complished, as  far  as  our  knowledge 
extends.  We  are  well  aware  that  ves- 
sels are  enlarged  in  a  variety  of  ways, 
but  let  us  inquire  how?  Is  it  not  often 
by  adding  to  the  number  of  dead-flat 
frames,  and  making  the  addition,  or 
the  part  added,  at  best  little  better  than 
a  box,  and  then  wonder  why  a  good 
modelled  ship  does  not  perform  to  our 
entire  satisfaction  ?  We  have  often 
heard  men  express  their  wonder  and 
surprise  at  the  tardy  movements  of  a 
ship  having  greater  length  than  another 
of  more  lively  motion  and  greater  speed, 
taking  it  for  granted,  that  length  was 
every  thing,  let  the  shape  be  what  it 
may. 

We  say,  that  when  a  ship  or  other 
vessel  is  to  be  enlarged  or  diminished 
in  size,  let  it  be  done  in  a  systematic 
manner  throughout.  There  is  enough 
of  piecing  and  patching  on  old  vessel-, 
without  commencing  in  the  loft. 
Many  vessels  have  been  spoiled  be- 
tween the  time  of  finishing  the  model 
and  that  of  making  the  moulds.  There 
is  no  difference  in  the  operations  oj 
enlarging  or  diminishing  on   the  floor 


30 


234 


MARINE    AND    NAVAL    ARCHITECTURE. 


of  the  loft,  or  on  the  draft;  in  the 
former  ease,  we  use  the  common  12 
inch  rule  ;  in  the  latter,  the  scale  upon, 
or  by  which  the  model  is  made.  The 
operations  are  identically  the  same; 
whatever  is  feet  and  inches  on  the  scale, 
is  the  same  on  the  rule  ;  and  in  con- 
cluding the  subject  of  enlargement  and 
reduction  in  the  size  of  vessels,  we  will 
add,  that  it  should  never  be  inferred 
tli at  because  the  two  ends  of  the  ves- 
sel is  like  the  model,  she  will  perform 
much  the  same,  though  the  middle  be 
altered.  We  have  known  ships  thus 
built  to  be  the  most  unwieldy  hulks  that 
could  well  be  imagined  ;  and  yet  the 
model,  if  built  by,  would  have  brought 
forward  a  fine  working  ship.  It  in- 
creases the  resistance  in  such  man- 
ner and  ratio,  that  the  builder  can  de- 
termine little  in  relation  to  it.  The 
stability,  it  is  true,  may  be,  and  is  very 
generally  increased,  and  it  is  taken  for 
granted  that  all  other  good  qualities 
increase  in  like  ratio.  Length  in  ships 
and  most  other  kind  of  vessels,  we 
readily  agree  is  a  most  efficient  quali- 
ty ;  but  let  it  go  where  it  belongs ;  let 
it  be  distributed  over  the  entire  vessel ; 
the  greatest  proportion  in  the  middle, 
or  yet  in  the  end,  will  not  do;  that  is 
to  say :  that  we  must  not  calculate  on 
the  performance  of  a  vessel  thus  al- 
tered from  the  original  calculations, 
without  going  into  the  second  arrange- 


ment, as  though  the  two  models  were 
not  designed  to  be  alike  in  any  particu- 
lar. To  take  from  or  add  to  the  length, 
breadth,  or  depth  of  a  vessel  after  (he 
building  operations  have  commenced, 
and  expect  the  same  uniform  results, 
is  an  anomaly  in  mechanical  science  ; 
yet  the  practice  prevails  to  a  very  great 
extent  throughout  the  United  States: 
and  ship-builders  regard,  as  of  little 
consequence,  the  addition  of  10  feet, 
for  example,  all  in  dead-Mats,  added  to 
a  ship,  that  it  can  make  no  sensible  dif- 
ference. We  remember  to  have  heard 
some  expressions  of  surprise,  that  two 
vessels  did  not  sail  equally  fast,  steer 
equally  well,  and  were  unable  to  carry 
an  equal  amount  of  sail,  when  it  was 
notorious  that  they  were  exactly  alike, 
the  one  being  only  3  or  4  feet  longer 
than  the  other  ;  it  could  not  be  in  the 
vessels;  it  must  of  necessity  be  in  work- 
ing the  vessel.  Thus  the  faults  of  the 
mechanic  are  packed  on  the  sailor  ; 
and  sometimes  when  the  mariner  is  at 
fault,  the  mechanic  must  bear  the 
blame.  An  arrangement  like  we  have 
described  very  generally  comes  upon 
the  builder  when  he  is  least  prepare 
to  meet  the  emergency.  The  ship  is 
often  required  in  four  months,  and  the 
alterations  are  seldom  thought  of  be- 
fore the  model  is  made,  and  afterwards 
are  made  upon  the  floor  with  impunity. 
AY  here  the  eye  determines  everything, 


MARINE    AND    NAVAL    ARCHITECTURE. 


235 


the  difference  cannot  be  discovered,  in- 
asmuch as  it  is  a  kind  of  guessing  ope- 
ration throughout,  and  we  would  be 
quite  as  likely  to  go  one  side  of  the 
mark  as  the  other.  We  are  aware 
that  we  stand  perhaps  quite  alone  in 
this  matter  of  enlarging-  at  random  ; 
but  we  had  rather  be  alone,  when  con- 
scious of  the  right,  than  on  the  popu- 
lar side,  and  in  the  wrong.  As  we 
have  doubtless  made  this  subject  suf- 
ficiently clear  in  the  preceding  chap- 
ters, no  farther  expositions  are  re- 
quired. 

We  left  the  floor  of  the  loft  the  sec- 
onn  time  on  page  183 — having  little 
more  to  do  before  entering  upon  the 
important  duties  of  laying  off  the  cants 
and  other  important  parts  of  the  struc- 
ture, until  the  reasons  were  given  for 
adopting  the  independent  course  we 
have  taken  in  designing,  as  well  as  in 
laying  off  ships.  It  is  not  enough  to 
know  how  a  thing  is  done,  the  why  is 
often  of  equal  consequence  ;  and  to 
pursue  the  course  others  have  done, 
viz.,  to  go  into  the  loft  and  not  leave  it 
until  the  whole  operation  is  performed, 
we  should  judge  would  be  much  the 
same  as  though  the  mechanic  who 
was  laying  down  the  vessel  was  to  con- 
tinue his  work  without  reference  to 
the  vessel  itself,  either  in  size,  space, 
or  adjustment. 

Having    carried  the   several  opera- 


tions along  together  as  near  as  we 
could  on  the  model,  the  floor,  and  the 
draft — not,  however,  by  leaving  either 
in  a  crude  state — both  the  draft  and 
the  floor  delineations  were  carried 
through  the  second  proof,  or  were  first 
transferred  to  the  floor  from  the  tables, 
faired  in  the  rotundity  of  their  longi- 
tudinal planes,  taken  from  thence  and 
applied  to  the  body-plan,  the  discrepan- 
cies regulated  in  the  body-plan,  and  the 
corrections  noted  on  the.  floor,  and  the 
water-lines  again  faired  and  made  to 
correspond  with  the  frames  of  the  body- 
plan.  This  operation  constituted  the 
first  proof,  and  if  the  necessary  care 
were  taken  in  the  performance  of  the 
work,  the  ship  woidd  come  to  the  rib- 
bands easier  than  many  vessels  we  have 
seen  that  had  been  carried  through  the 
second  proof  with  the  aid  of  diagonals. 
The  draft  also  was  carried  through  the 
several  stages  of  advancement,  and  we 
now  arc  brought  to  the  threshhold  of  an 
inquiry,  what  yet  remains  to  be  done 
upon  the  floor,  before  we  are  ready  to 
make  moulds?  We  answer,  more  than 
can  be  described  on  the  remaining 
pages  of  this  chapter. 

We  have  carried  the  lines  on  the 
floor  through  the  usual  test  of  their 
accuracy,  and  we  may  fairly  assume 
that  the  ship  is  delineated  in  her  full 
size;  and  doubtless  more  might  be 
learned  by  the  casual  observer  of  her 


23C> 


MARINE   AND    NAVAL    ARCHITECTURE, 


real  shape  from  the  floor  now  than  at 
any  subsequent  period,  after  a  more 
copious  effusion  of  lines  has  taken 
place.  The  body  has  been  faired  by 
horizontal  sections,  usually  called  wa- 
ter-lines ;  vertical  sections,  usually 
called  section  or  buttock-lines  ;  and  by 
oblique  sections,  usually  called  diago- 
nal lines.  The  sheer  and  half-breadth 
plans  have  been  divided  longitudinally 
into  equal  spaces  the  entire  length  of 
the  ship  ;  a  section  or  part  of  each  ex- 
tremity has  been  set  apart  for  the  cants 
or  half-frames,  standing  diagonally  from 
the  middle-line  ;  the  remaining  or  mid- 
ship portion  of  the  ship's  frame  will 
stand  at  right  angles  with  the  middle- 
line,  or  square  across  the  ship  ;  and  it 
might  be  supposed  that  it  will  only  be 
necessary  to  sweep  in  the  frames  with 
pencil  in  the  body-plan,  and  at  once 
commence  making  moulds  for  the 
square  body.  This  practice  is  quite 
common,  but  we  will  pause  and  inquire 
into  the  propriety  of  adopting  it.  We 
have  shown  that  a  broad  surface  should 
be  presented  to  the  timber,  for  the  bet- 
ter distribution  of  the  fastening,  even 
though  it  be  at  the  expense  of  the 
scantling  size  of  the  timber.  These  rea- 
sons apply  equally  well  to  the  frame 
composed  of  two  timbers  as  to  the  sin- 
gle futtock  or  timber  ;  but  it  has  been 
found  to  be  advantageous  to  the  ship 
to  make  the  distribution  of  surface  still 


more  general;  and  in  order  to  accom- 
plish this  successfully,  the  spaces  be- 
tween the  timbers  of  adjoining  frames, 
and  those  of  the  same  frame,  have  been 
about  equally  divided,  and  the  change 
has  been  atttended  with  beneficial  re- 
sults. As  a  general  rule,  'however* 
the  spaces  between  the  timbers  of  the 
same  frame  is  somewhat  less  than  that 
between  the  adjoining  frames;  but  for 
this  inequality  in  room  or  space,  we 
are  fully  persuaded  no  substantial  rea- 
son can  be  assigned,  inasmuch  as  tin; 
fastening  and  the  ventilation  of  the 
ship  is  much  better  aceommodaU'd, 
where1  the  room  between  the  timbers 
and  the  frames  are  equal,  apart  from 
the  advantage  of  having  the  plank  more 
equally  supported.  It  will  readily  be 
discovered,  that  to  separate  the  timbers 
as  has  been  described,  will  be  to  make 
two  moulding  edges  to  each  frame, 
which  if  the  ship  has  a  number  of  dead- 
flat  frames,  would  not  alter  their  shape; 
but  just  in  proportion  as  we  recede 
from  the  dead -flat  frame,  will  the 
moulding  edges  be  found  to  disagree  ; 
and  if  we  were  to  move  both  timbers 
of  the  frame  from  the  station,  equally 
divided  on  the  base  and  middle-line,  we 
should  require  a  new  division,  or  tli.it 
frame  to  be  newly  spaced.  But  the 
necessity  of  this  may  be  avoid(>d  by  al- 
lowing the  floor,  second  and  fourth  fut- 
tocks,  with  the  half  top-timber,  to  re- 


MARINE    AND    NAVAL    ARCHITECTURE. 


237 


main,  and  move  the  other  half  of  the 
frame  the  distance  of  the  opening  ;  that 
is  to  say — let  the  first  futtoek,  third 
fultock,  and  top-timber,  be  moved  jnst 
the  amount  of  the  opening;  if  the 
floors  face,  or  have  their  moulding-side 
toward  the  dead-flat,  both  in  the  fore 
and  after-body,  then  the  first  futtoek 
will  require  to  be  moved  aft  in  the  fore- 
i)ody,  and  forward  in  the  after-body ; 
in  this  case,  the  first  division  of  spaces 
should  have  furnished  the  dead- flat 
frame  with  a  larger  space  between  it- 
self and  A,  (or  the  first  frame  in  the 
fore-body,)  inasmuch  as  the  other  floors 
have  between  their  faces  or  moulding- 
sides  two  timbers  and  two  spaces, 
while  by  making  two  floors  face  to- 
gether, we  bring  two  timbers  and  three 
spaces  into  one  berth  ;  hence  it  must 
be  quite  apparent,  that  between  <2>  and 
A  we  require  more  space  on  the  keel, 
and,  as  a  consequence,  on  the  floor,  by 
just  the  amount  of  space  the  frames 
are  designed  to  be  apart,  than  that  of 
any  of  the  other  square  frames.  We 
have  known  the  frames  of  a  ship  to  be 
arranged  equal  distances  apart,  and  all 
the  floors  to  face  forward  ;  but  the  lia- 
bility to  mistakes  in  bevelling  the  tim- 
bers is  much  greater  when  this  me- 
thod is  adopted,  for  the  following  rea- 
son— the  floors  in  the  fore-body  bevel 
standing,  while  those  of  the  after-body 
bevel  under.    This  arrangement,  it  will 


be  at  once  perceived,  reverses  the  bevels 
of  all  the  timbers  in  the  fore-body,  which 
makes  the  operation  inconvenient,  in- 
asmuch as  it  subjects  the  operative  to 
the  liability  to  mistakes,  in  consequence 
of  his  having  been  accustomed  to  bev- 
elling all  the  timbers  of  the  same  de- 
nomination within  or  without  the 
square,  as  the  timbers  upon  which  he 
may  work  may  demand;  in  other 
words,  workmen  have  been  accustom- 
ed to  bevelling  all  the  floors  under,  and 
all  the  first  futtocks  standing :  this  is 
the  result  of  facing  all  the  floors  to  0, 
which  frame  also  faces  forward,  being 
in  the  after-body,  or  being  usually  re- 
cognized as  belonging  to  the  after-body. 
With  this  arrangement,  the  face  of  the 
floor  is  at  the  place  or  station  at  which 
the  moulds  are  designed  to  be  made  ; 
and  it  follows,  that  whatever  variation 
there  may  be  in  consequence  of  remov- 
ing the  first  futtoek  and  the  timbers 
butting  on  above,  from  their  proper 
place,  or  the  place  where  their  mould- 
ing-edge was  laid  down,  must  belong  to 
the  first  futtoek.  This  variation  does 
not  amount  to  any  very  considerable 
amount  for  pcrphaps  10  or  15  frames 
from  the  dead-flat,  when  it  becomes 
worthy  of  notice,  and  measures  should 
be  taken  for  removing  the  discrepancy. 
It  is  quite  common  to  make  but  one 
set  of  moulds  for  the  entire  square  body 
of  a  ship  ;  that  is  to  say — that  the  first 


23S 


MARINE    AND    NAVAL    ARCHITECTURE. 


futtock  mould  is  made  by  the  line  laid 
down  for  the  floor,  and  several  inches 
from  the  place  where  it  properly  be- 
longs: when  the  spaces  are  smaller 
between  the  moulding-edges  than  be- 
tween the  frames,  the  discrepancy  is 
not  as  apparent ;  but  where  they  are 
equal,  it  amounts  to  enough  to  justify 
its  removal.  We  have  said  that  there 
was  no  substantial  reason  for  making 
t  he  spaces  between  the  timbers  less  than 
those  between  the  frames;  and  the  only 
reason  is  found  in  the  desire  to  avoid 
the  trouble  of  laving  down  the  mould- 
ing-edge of  the  first  futtock  and  the 
timbers  butting  upon  it,  and  to  save 
the  increase  of  iron  in  the  extra  thick- 
ness of  the  chocks.  Whatever  may  be 
the  thickness  of  the  chock  between 
the  timbers,  it  will  seldom  be  necessary 
to  extend  the  two  lines  for  the  mould- 
ing-edges to  the  dead-flat  frame  ;  if, 
however,  the  ship  is  quite  round  lon- 
gitudinally, we  may  perceive  the  varia- 
tion extending  to  that  frame.  The  cases 
in  which  this  would  occur,  however, 
are  rare,  or  at  least  they  are  not  com- 
mon. 

There  is  another  method  often 
adopted,  and  with  abundant  success  as 
far  as  it  goes,  to  avoid  a  discrepancy 
in  the  moulding-edges,  or  to  bring  the 
moulding-edge  of  the  departing  timber 
back  near  its  proper  place.  The  floor 
in  this  case  as  before  remains  stationa- 


ry, with  its  face  in  the  same  place,  and 
the  size  of  the  chock  reduced,  which 
brings  the  remaining  part  of  the  frame 
nearer  the  place  at  which  the  mould 
was  made,  by  just  the  amount  of  the 
reduction.  Hence  it  is  quite  clear, 
that  if  the  chock  were  4  inches,  and 
its  reduction  2  inches  on  the  floor,  the 
other  part  of  the  frame  above  would  be 
removed  equal  distances  from  the  iiiu» 
at  which  the  mould  was  made,  inas- 
much as  the  face  of  the  second  futtock 
would  not  be  in  line  with  the  face  of 
the  floor.  This  method,  however, 
does  not  remove  the  difficulty  ;  it  mere- 
ly gets  around  it.  The  only  way  to 
effectually  remove  the  difference  is  to 
sweep  in  both  edges  ;  that  is  to  say — 
whatever  the  thickness  of  the  chocks 
may  be,  set  that  distance  oft*  both  in 
the  fore  and  after-body,  each  side  of  the 
line  representing  the  joint  of  the  frame 
on  the  floor.  And  now  we  will  give  the 
reason  why  the  setting-off  should  take 
place  both  sides,  or  each  side  of  the 
joint.  It  will  be  remembered  that  both 
the  fore  and  after-body  are  on  the  floor 
one  on  the  other ;  and,  as  a  conse- 
quence, the  same  straight  lines  across 
those  bodies  are  used  as,  and  repre- 
sent frames.  It  should  also  be  remem- 
bered that  the  two  bodies  face  toward 
each  other,  which  brings  the  fore-body 
first  futtocks  aft  of  the  joint,  while  the 
after-body  first   futtocks  are    brought 


MARINE    AND    NAVAL   ARCHITECTURE 


239 


forward   of  the  joints;   this  of  course 
makes  three  lines  on  the  floor — the  first 
for  the  face    of  the  floor,  the  second 
and  fourth  futtocks,  while  the  forward 
line  belongs  to  the  first  futtocks  of  the 
after-body, likewise  those  timbers  above, 
viz.,  the  third   futtock  and  top-timber. 
The   lines    aft  of  the  joint   represent 
the    first    and  third  futtocks   and   top- 
timber  joints  of  the    fore-body.      The 
frames  may   now  be  taken  off  on  the 
original  joint  of  the  frame,  or  the  mid- 
dle-line of  the  three,  which  represents 
the   floor,  second   and   fourth  futtocks, 
and  being  taken  from  the  half-breadth 
plan,  may  be  applied  and  swept  in  the 
square    body-plan    of  each  body  with 
pencil  or  red  chalk,  on  account  of  the 
liability  to  lose  the  lines   if   of  white 
chalk,  there  being  so  much  trampling 
on  the  lines  in  making  the  moulds  as 
to  render  it  necessary  to  have  the  lines 
marked  with  an  enduring  mark;  this 
precaution  is,  however,  not   necessary 
for  all  parts  of  the  work.      Great  care 
should  be  taken  to  get  the  batten  per- 
fectly fair,  and  to  mark  it  the   same, 
with  a  fine  and  distinct  line  ;   this  part 
of  the  work  being   done,  we  have  the 
lines  for  the  floor-mould  in  both  bodies, 
likewise  the  second  futtock,  fourth  fut- 
tock and  half  top-timber.     We    have 
in  this  example  taken  the  middle-line 
for  both  bodies;  that  is,  for  both  the 
fore    and    after-body.     We    may   now 


proceed  to  take  off  the  line  facing  the 
floor,  and  at   the  opposite  side  of  the 
chock,   its    thickness    determining   the 
distance.     If  we  take  off  the  after-body 
first,  we  take  the  lines  forward  of  the 
centre,  and  may  try  some  of  the  frames 
immediately  in  the  vicinity  of  the  dead- 
flat  frame.    If  the  variation  amounts  to 
anything,  or    if  space   enough    is  left 
between  the  lines  to  distinguish  them 
apart,    we    may    take    them   off   with 
care  from  the  half-breadth,  and  apply 
them  in  the  body-plan,  but  remember- 
ing to    mark  or  distinguish  them  by  a 
different  color  ;   that  is  to  say — if  the 
first  line   were  blue,  or   a  lead-pencil 
line,  let  this   be  a  red  chalk  line,  and 
made   with  an  equal  amount    of  care, 
as  fine  and   as  clear  as  may  be  ;   when 
the   after-body   is   swept   in    the   man- 
ner described,  we  may  proceed  to  the 
fore-body  in  the  same  manner,  but  with 
this   exception — in   the    after-body   we 
took  off  the  line  forward  of  the  original 
joint,  but  in  the  fore-body  we  take  off 
the  line  aft  of  the  middle  or  line  show- 
ing the  station  of  the  floor  ;   in  other 
respects  the  operations  are  the  same, 
and  require  an  equal   amount  of  care. 
It  will  doubtless  be  at  once  discovered, 
that   the  moulds  should  not  all  be  made 
by  either  of  those  lines  ;   the   former  is 
designed,   as   we   have    stated,    for  the 
floor,  second  futtocks.  fourth  futtocks, 
and   all  the  timbers  that   butt   on   the 


240 


MARINE    AND    NAVAL    ARCHITECTURE 


floor-side  of  the  frame.  As  -we  have 
also  stated,  this  practice  is  rarely  ad- 
hered to  the  entire  length  of  the  square 
body,  and  to  avoid  the  eost  or  trouble 
of  doing  this,  the  ehocks  are  often  made 
thinner  than  they  would  otherwise  be. 
With  the  arrangement  as  we  have  de- 
scribed in  the  distribution  of  timber,  the 
ship  is  not  only  actually  stronger,  but 
nearer  the  shape  she  was  designed  to 
be. 

We  have  thus  carried  our  readers 
through  the  operations  of  the  floor  in 
relation  to  the  square  body  of  the  ship, 
or  those  frames  that  have  floors  ap- 
pended to  them,  and  stand  at  right  an- 
gles with  the  keel.  It  is  sometimes 
the  case,  however,  that  it  is  not  neces- 
sary to  commence  the  canting  of  the 
frames,  and  yet  the  frame  has  so  much 
rise  that  we  cannot  obtain  floors ;  this 
may  be  known  before  the  cants  are 
laid  down,  and  the  arrangements  made 
accordingly.  Such  are  called  box 
frames,  and  would  be  framed  and  boxed, 
or  morticed  into  the  dead-wood  at  their 
heels,  in  the  same  manner  as  the  cants, 
but  still  stand  thwartship,  or  at  right 
angles  with  the  keel.  These  frames  may 
be,  and  are  sometimes  found  on  each 
end  of  the  ship  at  the  same  time,  or  on 
both  ends  of  the  same  ship  ;  although 
box  frames  are  properly  square  frames, 
yet  they  may  with  propriety  be  classed 
among  the  cants,  for  these   reasons — 


the  order  of  Framing  is  changed  on  the 
floor  frames:  the  timber  boxing  in  or 
across  is  the  floor  or  short  timber, 
that  is  to  say,  short  on  each  side  :  bill 
on  these  box  frames,  the  timber  box- 
ing into  the  dead-wood  is  the  long  tim- 
ber, or  first  futtock ;  and  this  is  the 
same  as  the  cants.  But  although  llii> 
arrangement  is  quite  common,  we  can 
discover  no  good  reason  for  the  change: 
when  there  has  been  carelessness  in  tin 
loft,  and  an  equal  amount  in  framing, 
perhaps  the  change  is  an  advantage. 
in  consequence  of  the  liability  to  diffi- 
culty with  the  heel  against  the  side  of 
the  dead-wood,  when  the  frame  goes 
up  with  both  heel  timbers  on  ;  in  such 
cases  the  short  timber  is  left  oft",  and 
put  up  afterwards.  Another  reason, 
however,  is  usually  assigned,  which  is 
this — that  the  frame  is  rendered  strong- 
er  by  boxing  in  the  longer  timber  ;  this 
we  regard  as  a  mooted  point,  and  shall 
leave  its  settlement  in  the  mind  of  the 
builder,  being  satisfied  in  our  own  mind 
that  it  is  of  no  material  consequence, 
whether  the  long  or  the  short  timber 
is  boxed  into  the  dead-wood.  This 
should  be  remembered,  that  the  timber 
that  stands  fast  on  the  floor  of  the  loft. 
is  the  floor-side  of  the  frame,  remain- 
ing stationary,  while  the  first  futtock 
side  of  the  frame  moved  the  thickness 
of  the  chock  ;  on  the  box  francs  we 
may  box   in  which  we  please.      These 


MARINE   AND    NAVAL   ARCHITECTURE. 


241 


frames  are  equally  as  strong  as  cant 
frames,  and  sufficiently  so  for  their  lo- 
cation, if  properly  fastened  to  the  dead- 
woods  at  their  heels.  There  are  sel- 
dom more  than  two  of  these  frames  at 
each  end  of  the  ship,  and  only  where 
little  cant  is  required  to  fill  the  open- 
ing above.  The  heels  of  the  timbers 
of  these  frames  end  at  the  bearding- 
line,  and  have  no  connection  with  the 
line  showing  the  seats  of  the  floor,  as 
seen  in  Plate  8. 

We  have   but  one   other  exposition 
to  give  in  this  .  liapter  in  relation  to 


the  square  body-plan  on  the  floor  of  the 
mould-loft,  believing  that  the  subject 
has  been  made  clear  to  every  discern- 
ing mechanical  mind.  In  taking  off 
the  frames  from  the  half-breadth  to 
apply  to,  and  sweep  in  the  body-plan, 
we  should  work  by  the  diagonal  lines, 
inasmuch  as  they  come  nearer  at  right 
angles  with  the  shape  of  the  frame, 
even  though  taken  off  horizontally, 
and  the  nearer  square,  measurements 
are  taken,  the  more  likely  to  be  cor- 
rect. 


31 


242 


MARINE    AND    NAVAL    ARCHITECTURE. 


CHAPTER    VIII. 

Cants  by  Water  Lines — Cants  by  Diagonals — Square  Stern,  witbout  stern  frame — Its  Advantages — Stern 

Frame — Instruction  for  Building  them — Making  Moulds. 


We  have  shown  in  a  previous  chap- 
ter that  the  square  frames  do  not  ex- 
tend the  entire  length  of  the  vessel  un- 
less she  is  very  sharp,  like  some  of  the 
steamboats    running    on    the    Hudson 


running 


River  ;  we  have  also  shown  the  reason 
for  adopting  the  system  of  cant  frames 
in  this  country  some  fifty  years  ago ; 
and  although  we  invited  the  reader  to 
follow  us  in  taking  off  the  tables  from 
the  square  frames  extending  the  entire 
length  of  the  ship,  yet  we  had  no  in- 
tention of  making  moulds  by  the  frames 
swept  on  the  floor  to  the  entire  ex- 
tremity of  the  ship  ;  hence  the  reason 
of  our  setting  apart  a  space  at  each 
end  of  the  ship  for  cant  frames,  as  shown 
on  Plate  3,  and  on  Plate  7.  The  judg- 
ment of  the  builder  must  determine  the 
number  of  cant  frames  required,  and 
the  angle  of  obliquity  they  form  with 
the  middle -line,  or  side  of  the  keel. 
This  obliquity  must  increase  as  we  ap- 
proach the  extremities,  and  still  meet 
the  varying  form  of  the  ship. 

The  disposition  of  these  frames  may 
be  seen  in  Plate  16,  in  the  half-breadth 


plan.  Our  remarks  on  expansion  may 
be  referred  to  with  advantage  to  the 
reader,  even  though  he  may  have  built 
ships.  The  distribution  of  the  timber  . 
on  the  ends  of  the  ship,  is  a  matter  of 
some  moment,  both  with  respect  to 
economy  and  strength. 

The  disposition  of  cant  timbers  or 
frames  may  be  familiarly  illustrated  by 
the  swinging  of  a  door  upon  its  hinges, 
Avith  this  exception :  the  door  is  con- 
tinually hanging  upon  an  immoveable 
axis,  while  each  cant  has  its  own  axis. 
Assuming  a  door  to  be  open  to  an  an- 
gle of  90  degrees,  which  is  square  from 
the  partition  upon  which  it  is  hung, 
while  in  this  position  it  represents  a 
square  frame,  the  line  of  partition  re- 
presenting the  keel.  Let  the  quadrant 
or  quarter  circle  formed  by  the  outer 
edge  of  the  door  be  divided  into  as 
many  parts  as  there  are  cants ;  now 
close  the  door  to  the  first  division,  and 
we  have  the  angle  the  door  forms  with 
that  part  of  the  partition  to  which  the 
door  is  hung,  that  the  first  cant  does 
with  the  keel  from  forward.     The  same 


MARINE  AND    NAVAL   ARCHITECTURE, 


243 


may  be  said  of  any  and  every  other  one 
of  those  divisions  ;  when  we  have  the 
stern  frame  in  the  ship,  we  do  not  cant 
as  far,  but  when  we  have  a  round  or 
square  stern,  without  stern  frame,  we 
cant  the  whole  number  of  degrees  the 
quadrant  or  quarter  circle  contains. 
Many  persons  have  thought  that  the 
canting  of  frames  must  of  necessity 
swing  them  from  a  perpendicular  line 
on  the  dead-wood  ;  now  suppose  we 
examine  and  find  that  the  door  was 
plumb  on  both  edges,  or  at  the  hinges, 
and  at  edge  upon  which  the  lock  is 
placed,  we  now  mark  a  parallel  line 
eight  inches  from  the  hinges  toward 
the- outer  edge;  let  us  open  and  shut 
the  door,  trying  the  line  on  the  same, 
in  the  different  parts  of  the  circle,  we 
shall  find  that  in  any  position  we  may 
find  the  door,  the  line  will  still  be 
plumb.  Now  it  is  just  so  with  regard 
to  the  keel  ;  although  the  axis  of  the 
cant  is  at  the  centre,  yet  at  any  given 
distance  from  the  centre  the  cant  on 
the  dead-wood  is  square,  while  the 
dead-wood  or  its  sides  are  plumb  ;  and 
if  they  are  not  plumb,  they  should  be. 
Hence  we  say  emphatically,  that  all 
cants  should  be  square  from  the  base- 
line ;  but  we  may  illustrate  something 
more  by  the  door.  We  have  seen  that 
all  lines  that  are  parallel  to  the  axis 
are  plumb;  but  now  let  us  mark  out 
the  form  of  a  frame  on  the  door  end- 


ing the  heel  six  or  eight  inches  out- 
side of  the  hinges  ;  open  the  door  as  at 
first  to  90  degrees  from  the  partition 
or  square ;  mark  a  line  on  the  floor 
nearly  parallel  with  the  partition,  that 
is  to  say — let  the  widest  part  be  at  the 
edge  of  the  door  when  open,  and  taper 
as  the  side  of  a  ship  would  taper,  to- 
ward a  line  squared  out  from  the  edge 
of  the  door  when  shut.  We  may  di- 
vide the  sill  of  the  door  into  as  many 
parts  as  the  circle  has  been,  when  we 
have  the  whole  mystery  of  cant  frames 
illustrated.  We  discover  that  the  door, 
although  it  will  fill  out  from  the  hinges 
to  the  circle  at  any  angle,  yet  we  may 
shift  the  axis  to  any  of  the  settings-off 
corresponding  to  those  of  the  circle, 
and  we  shall  see  that  the  edge  of  the 
door  will  not  reach  the  line  represent- 
ing the  side  of  the  ship.  Hence  it  is 
plain,  that  although  the  ship  is  grow- 
ing narrower  the  farther  aft  we  go, 
yet  the  frames  require  to  be  longer,  on 
account  of  the  increased  cant,  that  is 
to  say — the  canting  increases  their 
length  faster  than  the  diminishing  of  the 
side  shortens  them,  which  would  be  the 
case   were  they  square  frames. 

The  wonder  we  think  must  cease 
when  the  subject  is  fully  considered  in 
the  manner  we  have  described.  Eu- 
ropean authors  have  confused  t lie  sub- 
ject of  cants  or  canting  frames  by  con- 
necting so  many  lines  with  the  process 


244 


MARINE    AND    NAVAL   ARCHITECTURE 


of  instruction.  The  mystery  of  cant 
frames  is  not  as  great  as  their  exposi- 
tions would  seem  to  indicate,  (judging 
from  the  number  of  lines  made  use  of 
or  employed  in  the  operation.)  They 
first  endeavor  to  show  us  how  to  lay 
off  cants  by  what  they  term  level  lines, 
or  lines  running  parallel  to  the  base- 
line ;  and  again,  by  a  second  set  of  lines 
they  term  water-lines,  as  though  all 
linos,  whether  running  parallel  to  the 
keel  or  to  the  surface,  were  not  water- 
lines.  We  would  like  to  know  what 
need  there  is  to  make  a  distinction  in 
lines  that  should  be  exactly  alike,  par- 
ticularly in  illustrating  this  subject,  un- 
less it  be  to  confuse  the  mind  of  the 
reader.  We  have  endeavored  to  divest 
the  subject  of  everything  that  is  not 
absolutely  necessary  to  illustrate  the 
matter  fully. 

It  is  true  we  will  show  the  manner 
of  laying  off  the  cants,  both  by  water- 
lines  and  by  diagonals,  but  this  is  ne- 
cessary, inasmuch  as  vessels  may  be 
built  without  the  use  of  diagonals,  al- 
though a  valuable  acquisition  in  the 
loft  for  the  purpose  of  proving  frames  ; 
and  again,  in  the  third  series  of  lines 
we  shall  show  the  advantages  of  laying 
off  cants,  by  the  section  or  buttock- 
lines,  as  they  are  sometimes  called. 

As  we  have  before  said,  we  must  dis- 
pose of  the  cants  first  in  the  half- 
breadth  plan,  where  they  are  seen  as 


straight  lines;  they  may  also  be  seen 
in  the  sheer-plan,  but  are  not  neCesr 
sarily  so,  unless  in  some  more  than  or- 
dinary cases.  We  may  show  their  shape 
in  the  body-plan,  or  we  may  make  a 
cant  plan  on  a  separate  part  of  the  floor, 
as  shown  in  the  draft,  Plate  7.  It  is 
seldom,  however,  that  this  is  rendered 
necessary,  inasmuch  as  the  body-plan 
is  sufficiently  large  to  keep  the  cant 
within  the  square  frame  under  ordinary 
circumstances, or  when  we  have  a  stern 
frame.  Hence  we  discover  that  it  is 
more  convenient  to  use  the  square  body 
when  we  can.  In  cases  where  we  de- 
termine to  have  no  stern  frame,  and 
yet  have  a  square  stern,  we  would  re- 
commend a  separate  plan  for  the  cants, 
as  shown  on  the  draff,  Plate  7.  It 
must  be  remembered,  that  in  laying  off 
the  cant  frames,  the  side  line,  although 
seemingly  a  fictitious  line,  is  really  the 
size  of  the  keel  in  the  direction  in  which 
it  is  shown  ;  and  that  we  require  a  dif- 
ferent side  line  for  every  cant.  Thus 
we  perceive  that  we  have  no  connec- 
tion with  the  original  side  line  used  for 
the  square  frame,  inasmuch  as  we 
have  shown  by  the  similitude  of  the 
door,  that  although  the  side  tapers  as 
we  approach  the  stern,  the  frames  con- 
tinue to  extend  farther  out  as  we  con- 
tinue to  cant  them  more.  It  is  even 
so  with  the  side  line,  in  one  particular,  ' 
at  least  ;  the  exception  may  be  found  in 


MARINE    AND    NAVAL    ARCHITECTURE. 


245 


the  parallel  thickness  of  the  keel.  The 
ending  of  a  cant  is  somewhat  analo- 
gous to  the  ending  a  diagonal  line 
swung  off  as  we  have  shown  ;  the  va- 
riation is  found  in  the  direction,  or  the 
angle  upon  which  the  keel  is  measured  ; 
and  although  some  of  the  cants  may 
extend  outside  the  square  frames,  it 
should  not  surprise  the  inquirer. 

The  practice  of  drawing  drafts  and 
of  building  ships  with  a  drag-line  in 
Europe,  has  seemed  to  envelop  the 
subject  of  cant  frames  in  mystery,  or 
at  least  the  subject  has  been  made 
much  darker  to  the  mind  of  the  learner 
than  it  would  otherwise  have  been  ; 
we  mean  by  the  dragline  greater 
draught  of  water  aft  than  forward,  the 
consequence  of  which  is,  that  the  load- 
line  is  not  parallel  to  the  base-line,  and 
the  water-lines  form  a  curved  line  in 
the  body-plan,  and,  consequently,  the 
lines  on  the  cants  alter  their  heights  ; 
which  adds  to  the  complexity  of  the  sub- 
ject. This  practice  has  been  abandoned 
in  the  United  States,  or  at  least  in  the 
general  sense,  and,  as  a  consequence, 
the  lines  are  found  to  be  parallel  to  the 
base-line.  In  view  of  this  arrangement, 
it  must  be  quite  clear,  that  in  swinging 
the  cant  around  from  the  position  of  a 
square  frame,  the  lines  neither  rise  or 
fall,  that  is — the  water-lines  on  the  bow 
do  not  find  a  lower  place  on  the  frame, 
neither  do  the  after  cants,  when  swun# 


around,  cause  the  lines  to  rise  on  the 
frame,  in  order  that  their  proper  height 
may  be  obtained.  The  sheer-lines  are 
found  to  be  higher  on  the  cants  than 
on  the  square  frames  on  both  ends  of 
the  ship,  inasmuch  as  the  bow  and  stern 
are  both  higher  than  their  respective 
square  frames ;  the  consequence  of 
this  rise  makes  it  necessary  to  square 
up  from  the  half-breadth  plan  the  cross- 
ing of  the  cant  on  every  sheer-line  re- 
spectively; in  other  words,  in  the  half- 
breadth  plan,  where  the  cant  crosses  the 
first  breadth  ;  take  the  distance  of  that 
spot  from  the  last  square  frame,  and 
carry  that  distance  up  to  the  sheer- 
plan,  and  mark  on  the  first  height  the 
same  distance,  so  of  every  other  cant 
and  sheer-line  ;  the  crossing  being  no- 
ted in  the  sheer-plan,  the  heights  may 
be  taken  on  the  respective  cant  frames, 
and  carried  to  the  body-plan,  and  be- 
ing lined  across  as  in  the  case  of  square 
frames,  the  body-plan  is  prepared  for 
t  he  half-breadths.  In  drawing  the  dra  ft 
it  is  usual  to  square  up  the  crossing  of 
the  water-lines  to  the  sheer-plan,  that 
is  to  say — the  spot  where  the  cant 
frame  in  the  half-breadth  crosses  the 
water-line  is  squared  up  to  the  same 
line  in  the  sheer-plan,  where  its  cross- 
ing is  also  marked;  the  crossing  of  the 
side  line  by  ihe  cant  is  also  squared  up 
to  the  sheer-plan,  and  marked  on  the 
bearding     line;     a    batten   applied    to 


246 


MARINE   AND    NAVAL    ARCHITECTURE. 


these  several  spots  will  show  the  square 
view  of  the  cant  frame  ;  this  line,  how- 
ever, is  seldom  required  in  its  full  length 
on  the  floor  of  the  mould  loft,  although 
it  not  unfrequently  occurs  that  some 
one  or  more  of  the  spots  are  required 
for  the  purposes  of  proof,  &c. 

We  have  shown  the  manner  of 
striking  in  the  cants  in  the  half-breadth, 
that  the  openings  be  regulated  on  the  top- 
side, or  on  the  first  breadth,  and  that 
there  be  sufficient  room  for  the  heels 
against  the  dead-wood.  If  the  ship  be 
full,  we  are  apt  to  crowd  so  many  cants 
in,  that  the  heels  require  to  be  tapered, 
whereas  had  the  ship  been  sharper,  we 
might  have  had  a  sufficiency  of  room. 
It  would  be  better  to  have  room  enough 
for  the  heels  to  be  kept  apart,  even 
though  we  had  to  put  in  more  timber 
above.  It  is  even  more  essential  that 
cant  frames  should  be  kept  apart  by 
the  introduction  of  chocks  than  square 
frames.  It  is  quite  recently  that  chocks 
have  been  introduced  between  the 
moulding  edges  of  cant  frames,  although 
it  has  been  practised  in  Europe,  but  not 
to  any  considerable  extent  ;  but  we 
say,  that  the  chocks  should  be  thicker 
at  the  head  than  at  the  heel  of  the 
frame,  making  the  distribution  more 
equal.  It  may  be  objected  to,  on  the 
ground  that  a  tapered  chock  would  be 
difficult  to  fit,  inasmuch  as  the  thick- 
ness  is   only    parallel  at   parallel    dis- 


tances from  the  centre  or  side-line. 
To  this  objection  we  answer,  that  it 
would  be  an  easy  matter  to  mark  a 
parallel  or  plumb  line  on  the  mould  at 
the  sirmarks,  and  we  have  all  we  re- 
quire;  the  advantage  of  such  an  ar- 
rangement to  the  ship  would  be  more 
than  an  equivalent  for  the  trouble. 

In  a  former  chapter  we  have  shown 
another  manner  of  disposing  of  the  sur- 
plus timber  below  on  the  cant  frames, 
by  substituting  a  single  timber  for  the 
frame.  This  would  be  much  better  than 
the  present  method  ;  but  in  either  case, 
the  chocks  between  the  timbers  of  the 
frame  should  not  be  dispensed  with, 
and  we  may  make  the  chocks  to  taper 
or  parallel  as  we  please.  If  we  adopt 
the  chock,  we  must  line  their  thickness 
in  the  half-breadth  plan,  and  proceed  in 
the  same  manner  to  take  them  off  that 
we  did  the  square  frames.  When  we 
took  off  the  half-breadths  in  the  square 
body,  we  applied  the  batten  on  the  line 
showing  the  frame  ;  we  do  the  same  in 
this  case,  by  applying  the  end  of  the 
batten  to  the  middle -line :  the  batten 
extending  along  the  line  showing  the 
moulding  edge  or  joint  of  the  frame 
spotting  on  the  batten,  the  line  we  de- 
sire to  take  off;  this  is  applied  to  the 
body-plan  in  precisely  the  same  man 
ner  that  a  square  frame  would  be. 
This  operation  must  be  performed  on 
each  side  of  the  chock,  and  the  frames 


MARINE    AND    NAVAL    ARCHITECTURE. 


247 


may  be  swept  in  with  pencil  and  red 
chalk,  to  distinguish  them  as  in  the  ex- 
ample of  the  square  frames. 

In  arranging  the  cants  in  the  half- 
breadth  plan,  there  are  two  things  to 
be  considered,  both  in  the  forward  and 
after-body,  in  addition  to  the  ordinary 
size  of  openings ;  and  although  the 
subject  we  are  about  to  introduce  has 
found  its  way  into  separate  chapters 
and  articles  by  cotemporary  writers 
upon  this  subject,  yet  we  believe  it  re- 
quires a  notice  in  this  place,  inasmuch 
as  it  is  immediately  connected  with  the 
division  of  the  cants  in  the  half-breadth 
plan.  For  example,  the  stern  frame 
is  immediately  connected  with  the 
cants,  inasmuch  as  the  after  cant  tim- 
ber forms  the  boundary  line  of  the  stern 
frame,  and  is  commonly  known  by  the 
name  of  fashion  piece  ;  the  moulding- 
edge  of  this  timber  defines  the  length 
of  all  the  transoms ;  and  if  we  adopt 
the  prevailing  custom  of  canting  the 
frames  but  little,  the  fashion  piece 
would  have  a  place  on  the  side  of  the 
ship,  as  also  the  end  of  the  main  tran- 
som, some  few  inches  of  which  is 
usually  shown  on  the  first  breadth,  or 
about  half  of  its  size  on  the  end.  With 
these  remarks  before  him,  we  think  the 
pupil  will  be  better  qualified  for  divid- 
ing the  half-breadth  of  the  after-body. 

We  have  said  that  the  fashion  piece 
was  a  single  timber  ;  it  is  not  neces- 


sarily so,  unless  we  so  determine,  as  we 
shall  show  in  the  proper  place  ;  we 
will  add,  however,  that  it  is  not  a  cant 
frame,  but  belongs  to  the  stern  frame, 
although  its  location  must  be  shown 
before  we  can  arrange  the  cants  ;  that 
is — if  we  determine  upon  the  usual  size 
and  mode  of  building  it.  Thus  much 
for  the  interruption  on  the  stern  or 
after-end  of  the  ship. 

The  remainder  of  our  remarks  were 
reserved  for  the  bow  of  the  ship,  al- 
though the  forward  cant  in  the  fore- 
body  is  not  confined  in  the  maimer  the 
fashion  piece  is  in  the  after-body,  yet 
it  has  a  connection  that  is  worthy  of 
our  notice,  inasmuch  as  the  opening 
on  the  rail  may  lead  us  to  suppose  that 
we  may  equalize  the  division  between 
the  frames.  This  need  not  be  done. 
There  are  other  timbers  that  have  a 
place  in,  and  form  a  part  of  the  bow, 
the  heels  of  which  are  cut  off  by  the 
side  of  the  forward  cant ;  hence  it  must 
not  be  inferred  that  the  cants  are  de- 
signed to  fill  the  entire  space  unoccu- 
pied by  the  square  frames  ;  the  knight- 
heads  and  hause-pieccs  heeling  against 
the  forward  cant,  admonishes  us  that 
a  portion  may  be  reserved  to  advan- 
tage for  those  timbers,  a  detailed  ac- 
count of  which  will  be  found  in  this 
chapter.  With  these  distributive  re- 
marks relative  to  the  cants,  we  proceed 
without  delay  to  the    continuation  of 


248 


MARINE    AND    NAVAL    ARCHITECTURE. 


the  taking  off  process.  It  is  assumed 
that  the  lines  are  rendered  perfectly 
fair  before  we  begin  to  take  off  the 
cants,  having  been  proved  by  the  water, 
diagonal,  and  section-lines,  in  connec- 
tion with  the  continued  square  frames 
that  were  extended  to  the  extremities. 
Hence  it  only  remains  to  take  off  the 
cant  frames,  or  their  distances  on  the 
cant  from  the  middle-line  to  the  re- 
spective lines,  and  set  off  in  the  body 
or  cant  plan  in  the  same  manner  as  ap- 
plied in  the  square  body. 

In  this  exposition  of  the  cant  frames, 
it  may  not  be  necessary  to  go  as  fully 
into  the  various  modes  of  obtaining 
the  bevels  of  the  cants,  as  in  the  re- 
marks connected  with  the  cants  by  di- 
agonals. In  the  half-breadth  plan  the 
practice  has  become  quite  prevalent  of 
setting  off  the  size  of  the  timber  each 
side  of  the  joint  or  moulding-edge,  as 
shown  in  Plate  15.  In  this  case,  to  the 
line  showing  the  joint  of  the  frame 
when  there  is  no  chock,  (as  we  have 
said  chocks  in  the  cant  frames  are 
of  recent  date  in  the  United  States,) 
a  square  is  applied  to  this  line  showing 
the  joint  in  the  half-breadth,  the  stock 
with  the  line,  and  extending  to  the 
intersection  with  the  middle-line.  At 
this  junction  the  tongue  of  the  square 
is  first  one  way  and  then  the  other,  or 
first  up  and  afterwards  down ;  this,  of 
course,  makes  a  line  at  right  angles 


with  the   joint  of  the  frame  ;  the  size 
of  the  timber  is  then  set  off  from  the 
joint  each  way,  both  forward  and  aft, 
and  the  half-breadths  taken  off  a  sec- 
ond and  third  time,  and  applied  in  the 
body-plan;  that  is   to  say — from  this 
square  line  the   batten    is   applied  on 
each  of  the  last  two  lines  representing 
the  bevelling  edges  of  the  timber.      It 
follows,  as  a  consequence,  that  one  line 
will  come  within  the    moulding-edge, 
and  the  other  without;   or  we  may  ex- 
press it  different — one  line  will  come 
aft  and  the  other  forward  of  the  joint; 
that  is  to  say — the  one  will  bevel  stand- 
ing and  the  other  under,  for  this  rea- 
son :  it  will  be  observed,  that  this  me- 
thod is  virtually  trying  a  square  across 
the  frame,  to  see  the  amount  of  bevel 
given  by  the  gathering  in  of  the  lines. 
It  may  be  thought  by  the  reader,  as  it 
has  been  often  expressed    by    the  in- 
quirer, why  not  apply  the  square  in  the 
half-breadth  plan,  and  avoid  all,  or  a 
portion   of  this   work,  by    taking    the 
difference  from  a  square  within  or  with- 
out, and  applying  the  same  to  the  bevel- 
ling board,  so  many  lines  might  be  saved, 
and  thus  the  liability  to  mistakes  pre- 
vented ?     We  have  often  listened,  or  at 
least  more  than  once,  to  questions  like 
the  foregoing;  and  if  the  reader  will  be 
quiet,  wre  will  tell  him  in  a  few  words 
the  objections  to  his  proposed  plan  of 
taking  off  the  bevellings. 


MARINE    AND    NAVAL    ARCHITECTURE. 


249 


It  is  well  known  to  those  who  have 
worked  out  a  ship's  frame,  that  the  only 
correct  method  of  applying  the  bevel 
is,  that  of  placing-  the  stock  as  near  at 
right  angles  with,  or  square  from  the 
moulding-edge  as  may  be,  the  tongue 
will  then  incline  neither  way  ;  and  if  a 
square  were  applied  to  the  tongue  from 
the  face  of  the  timber,  it  would  be 
found  to  hang  down  at  right  angles 
with  the  face.  It  is  also  well  known  that 
if  the  heel  of  the  stock  be  turned  either 
way,  or  in  either  direction,  the  true 
bevel  cannot  be  applied  without  much 
trouble  ;  and  we  may  safely  say,  that 
for  general  purposes,  it  is  not  correct. 
Hence  it  follows,  that  the  bevel  to  be 
taken  correctly,  and  applied  equally  so, 
must  be  taken  square  from  the  mould- 
ing-edge, and  this  can  only  be  done  in 
the  body-plan  ;  that  is  to  say — no  one 
set  of  lines  running  longitudinally  will 
cut  all  the  frames  at  right  angles  ;  al- 
though the  diagonals  come  much  near- 
est,  yet  they  are  not  reliable  to  furnish 
the  bevels  in  the  manner  we  have 
shown,  or  in  the  direction  of  the  line. 
The  lines  in  the  body-plan  showing  the 
bevelling  edges  of  the  timbers,  may, 
and  indeed  should  be  swept  in  with 
while  chalk.  Then  there  need  be  no 
mistakes  ;  the  two  inner  lines  show,  the 
oik!  the  moulding,  the  other  bevelling 
edge,  and  whatever  the  one  falls  with- 
in   the  other,  when  measured  square. 


this  will  be  the  bevel,  as  in  Plate  15; 
thus  it  must  be  apparent,  that  if  the 
spots  are  carefully  made,  and  as  care- 
fully applied,  there  can  be  no  doubt  the 
spots  will  furnish  a  fair  line  in  the  body- 
plan,  and  the  bevel  can  be  taken  off 
anywhere  at  any  spot  we  please,  re- 
membering that  by  this  method,  as  in- 
deed all  methods  from  the  body-plan, 
when  the  white  chalk  line  is  inside 
the  black  or  red  line  showing  the  mould- 
ing-edge,  the  bevel  is  under,  when  with- 
out, the  bevel  is  standing,  and  where 
they  cross  each  other,  there  is  no  bevel, 
the  timber  is  square.  We  are  aware 
that  we  arc  departing  from  the  usual 
course  in  bevelling  cants,  before  having 
even  proved  them,  but  we  are  also 
aware  that  the  stiff  stereotyped  custom 
of  European  Naval  Architects,  has 
prevented  the  young  and  inquiring  as 
pirant  from  holding  the  thread  of  rea- 
soning their  pages  contain  ;  hence  the 
reason  why  we  have  followed  up  with 
the  bevels,  believing  that  one  will  as- 
sist to  explain  the  other. 

We  think  enough  has  been  said  re- 
lative to  the  manner  of  taking  oft'  the 
cants  by  water-lines  ;  we  may  or  may 
not  prove  them,  as  we  please:  they  are 
not  generally  taken  off  by  water-lines, 
and  when  they  are,  they  should  lie 
proved  by  section-lines;  particularly 
the  after-cants.  We  have  shown  the 
manner  of  squaring  up  the  crossing  of 


32 


250 


MARINE  AND    NAVAL    ARCHITECTURE. 


the  water  and  sheer-lines  by  the  frames, 
and  of  sweeping  the  curve  by  those 
spots  ;  this  is  termed  the  thwartship 
view,  or  the  actual  shape  presented  to 
the  eye  when  abreast  the  station  of 
the  cant  on  the  keel.  We  have  said 
that  it  was  not  necessary  to  sweep 
them  in  on  the  floor,  and  only  on  the 
draft;  we  may  add,  that  if  we  would 
show  the  cants  as  swept  by  water-lines 
in  the  manner  described,  and  proved 
by  section-lines,  we  cannot  well  dis- 
pense with  those  thwartship  views  in 
the  sheer-plan.  The  manner  of  prov- 
ing the  cants  by  section-lines  is  not 
complicated  ;  the  section-lines  have 
been  shown  in  the  sheer-plan  in  Plate 
4,  where  they  cross  the  frames,  as 
shown  in  the  square  view  ;  there  the 
height  must  be  taken  and  applied  to 
the  same  frame,  and  on  the  same  sec- 
tion-line in  the  body-plan.  The  man- 
ner of  running  the  section-line  in  the 
halt-breadth  body  and  sheer-plans,  has 
been  explained  on  page  136,  and  on- 
ward ;  or  as  we  have  before  remarked, 
that  if  the  spots  only  are  necessary,  the 
line  need  not  be  run  in  to  exhibit  this 
cross  view  in  the  sheer-plan.  We  are 
aware  that  more  lines  on  the  floor  than 
is  absolutely  necessary,  is  objectiona- 
ble. We  may  apply  this  proof  by  tak- 
ing the  height  on  every  frame,  and  on 
every  section-line,  and  if  they  agree, 
they  are  correct,  without  doubt.     In- 


asmuch as  the  cross-seam  intercepts 
all  intercourse  between  the  section  and 
sheer-lines  in  the  after-body,  we  need 
no  farther  proofs  above  the  outer  sec- 
tion-line, because  the  round  of  the  side 
on  the  breadths  or  longitudinally,  is  so 
small  that  it  can  hardly  be  imagined 
that  any  discrepancy  should  exist,  it 
proper  care  has  been  taken  in  the  trans- 
fer. 

It  may  be  fairly  assumed  that  enough 
has  been  said  in  connection  with  the 
illustrations  given,  to  make  the  subject 
of  cant  frames  by  water-lines  sufficients 
ly  clear  to  the  thinking-man ;  and  we 
now  enter  upon  the  duty  of  giving  ex- 
positions upon  another  method  of  de- 
lineating cant  frames  upon  the  floor, 
and  upon  the  draft,  which  we  think  we 
hazard  nothing  in  assuming  to  be  more 
practical.  We  have  already  explained 
the  position  and  angle  of  cant  timbers 
in  the  three  plans,  viz.,  sheer,  half- 
breadth,  and  body-plans.  We  would 
here  remind  the  reader  of  a  striking 
feature,  to  which  we  have  referred  in 
cant  timbers — it  is  well  known  that  in 
square  frames  if  the  frame  were  cut  by 
the  line  furnished  in  the  sheer-plan  and 
half-breadth  plan,  that  it  would  show 
the  actual  shape  of  the  frame,  anil  yet 
the  line  would  be  a  straight  line  in  both 
plans.  This,  as  we  have  observed,  is 
not  the  case  with  cant  frames;  they 
cannot  by  any  possible  means  exhibit  a 


MARINE    AND    NAVAL    ARCHITECTURE, 


251 


straight  line  in  the  sheer-plan.  The 
eye,  it  is  assumed,  moves  no  faster  than 
tin*  stations  on  the  side-line  would  re- 
quire, which  would  be  90  degrees,  or 
square  from  the  keel  ;  hence  it  is  plain, 
that  although  this  position  would  ex- 
hibit a  straight  line  in  the  square  body, 
the  canting  must  form  a  curved  line  in 
the  sheer-plan  ;  and  the  greater  the 
cant,  the  more  curvature  will  be  shown 
in  the  sheer-plan.  This  matter  of  ex- 
hibiting the  form  of  cants  on  the  floor, 
is  rarely  attended  to  ;  but  on  the  draft 
the  principle  of  canting  cannot  be  fully 
explained,  unless  attended  to.  Lest  by 
dividing  of  the  half-breadth  (or  that 
portion  set  apart  for  cant  frames)  into 
double  sections  to  admit  of  chocks  be- 
tween the  timbers,  we  should  confuse 
rather  than  instruct,  we  will  first  lay 
them  off  as  though  the  moulding  sides 
were  to  come  together.  We  must  first 
observe  the  crossing  of  the  diagonal  by 
the  cant  we  arc  about  to  take  oft.  It 
will  be  remembered  that  the  diagonal 
line  in  the  body-plan  forms  a  straight 
line  ;  we  must  take  oft'  the  cant  from 
the  spot  where  the  crossing  takes  place 
to  the  middle-line  square,  so  that  the 
distance  from  the  place  of  crossing  to 
the  middle-line  will  be  shorter  than  any 
other  direction  we  could  possibly  find  ; 
this,  as  a  consequence,' will  be  square. 
We  will  now  apply  this  to  the  body- 
plan  in  the   same   manner,  by  holding 


the  batten  horizontal,  and  moving  it  up 
or  down,  until  the  spot  we  have  taken 
from  the  half-breadth  intersects  the 
diagonal,  and  at  the  same  time  the  end 
of  the  batten  is  at  the  middle-line,  mark 
this  intersection  horizontally  across  the 
diagonal,  and  several  inches  outward; 
we  then  take  the  batten  again  to  the 
half-breadth  plan,  and  apply  it  in  the 
direction  of  the  cant  along  the  straight 
line  showing  the  frame  ;  the  end  of  the 
batten  as  before  at  the  middle-line, 
mark  the  crossing  at  the  same  identi- 
cal spot  on  the  floor  we  had  before  on 
the  batten,  the  only  difference  being  in 
the  place  of  the  heel  against  the  mid- 
dle-line ;  take  the  batten  again  to  tin; 
body-plan,  and  apply  it  in  the  same 
place  as  before.  It  will  be  discovered 
that  the  spot  on  the  batten  extends 
farther  out-board  than  before;  mark 
this  spot  last  taken  on  the  line  we  made 
when  here  first ;  this  spot  is  the  actual 
breadth  when  the  cant  is  in  its  place. 
The  first  breadth  taken  is  the  actual 
half-breadth  of  the  ship  at  the  station 
of  the  cant  on  the  side,  or  square  from 
that  point,  on  a  lint!  running  into  the 
middle-line,  and  square  with  the  same. 
The  operation  we  have  shown  in  list  be 
performed  with  every  diagonal  line. 
The  philosophy  of  this  operation  is  as 
follows — the  diagonal  in  the  body-plan 
takes  its  starting  point  from  the  mid- 
dle-line;  hence   it    follows,   that    inas- 


252 


MARINE    AND    NAVAL    ARCHITECTURE. 


much  as  the  stations  of  cants  are  square 
from  the  base-line  in  the  sheer-plan,  it 
follows  t  hat  the  diagonal  must  have  the 
same  application,  or  bear  the  same  re- 
lation to  the  cants,  so  that  when  we 
apply  the  diagonal  to  the  cant  frame, 
they  are  or  should  be  understood  as 
being  both  in  line  perpendicularly  from 
the  base-line,  and  at  the  proper  station 
on  the  side-line,  or  side  of  dead-wood. 
Now  it  must  be  quite  apparent,  that 
as  the  cant  is  swung  aft  on  the  stern, 
or  forward  on  the  bow,  we  bring  the 
station  of  the  cant  to  a  part  of  the  ship 
where  the  diagonal  is  higher  than  if 
the  frame  was  square ;  not  only  so, 
but  the  ship  is  narrower  at  this  new 
breadth  ;  and  we  shall  discover  that  the 
farther  aft  in  the  after  cants  we  pro- 
ceed, the  greater  will  be  the  difference 
between  the  two  breadths,  viz.,  the 
canted  and  the  square  breadth.  All 
the  diagonals  being  taken  off,  we  may 
square  np  the  crossing  of  the  sheer- 
lines  on  all  the  cants  up  to  the  sheer- 
plan  ;  transfer  the  height  so  obtained 
to  the  middle-line  of  the  body-plan, 
through  which  point  draw  a  level  line. 
In  the  half-breadth  plan  take  the  dis- 
tance; in  the  direction  of  the  cant  tim- 
ber from  its  intersection  with  the  sheer- 
line  to  the  middle-line  ;  apply  this  hull- 
breadth  on  the  height  to  which  it  be- 
longs in  the  body-plan,  and  continue 
the  same  operation  on  all  the  sheer- 


lines.  Having  shown  the  manner  of 
obtaining  the  form  of  the  moulding- 
edge  of  the  cant  frame  without  the 
chock,  we  may  proceed  to  delineate 
the  manner  of  performing  the  same 
with  the  chock. 

It  will  be  remembered,  that  in  our 
arrangements  for  the  admission  of  the 
chock  in  the  square  body,  the  original 
line  at  which  the  floor  was  placed  was 
permitted  to  stand  or  remain  unmoved, 
while  the  moulding-edge  of  the  first 
futtock  was  removed  its  proper  distance 
from  the  floor.  The  same  or  a  similar 
arrangement  will  apply  to  the  cants  ; 
the  moulding-edge  we  have  laid  down 
may  remain,  and  the  thickness  of  the 
chock  may  then  be  set  off,  inasmuch  as 
it  is  the  custom  to  reverse  the  order  of 
the  cants  ;  from  which  we  shall  discov- 
er that  the  line  we  already  have  in  the 
cant  body-plan  is  the  first  futtock.  The 
thickness  of  the  chock  may  now  be 
shown  by  another  line  being  stricken 
in  the  half- breadth  plan,  aft  (if  in 
the  after-body)  of  the  original  line ; 
they  may  be  tapering  or  parallel,  as  we 
please  ;  and  the  same  operation  may 
again  be  performed  in  transferring  the 
form  of  this  line  also  to  the  body-plan. 
These  two  lines  are  the  moulding-edges 
of  the  cants,  and  may  be  distinguished 
by  the  color  of  the  marks  upon  the  floor 
and  upon  the  moulds.  We  now  want 
to  determine  the  bevel,  inasmuch  as  (he 


MARINE  AND  NAVAL  ARCHITECTURE, 


253 


bevelling  edge  of  cants,  or  the  amount 
of  bevel  they  require,  may  and  should 
be  determined  at  the  same  time  ;  or  in 
other  words,  one  follows  the  other.  In 
our  delineations  of  the  performance  of 
this  part  of  the  work  by  water-lines, 
we  squared  a  line  across  the  joint  of 
the  frame  at  its  connection  with  the 
middle-line  ;  this  line  extended  the  sid- 
ing size  of  the  timber,  both  above  and 
below,  or  aft  and  forward.  This  we 
described  as  the  custom  very  generally 
adopted.  We  shall  in  our  expositions 
of  this  part  by  diagonals  pursue  a  some- 
what different  course.  At  the  conflu- 
ence of  the  joints  with  the  middle-line, 
we  may  square  up,  but  not  down,  as 
we  have  no  occasion  for  crossing  the 
middle-line.  We  may  now  apply  a 
•  straight  ed»e  across  the  timber,  or  its 
space  on  the  floor  ;  square  from  the 
joint  of  the  same,  or  the  straight  line 
showing  it — selecting  the  roundest  part 
of  any  of  the  lines  in  the  end  of  the 
ship  in  which  we  are  at  work.  The 
object  of  this  operation  is  to  determine 
how  far  across  the  frame  it  would  be 
safe  to  take  a  bevel,  in  order  that  the 
same  may  be  reversed  and  apply  equal- 
ly well  to  both  timbers.  It  is  quite 
evident,  that  if  the  straight  ei\ge  were 
carried  or  applied  the  whole  siding  size 
of  the  timber,  and  if  the  bevel  this 
would  furnish  were  reversed,  it  would 
not  be  at  all  adapted  to  the  opposite  tim- 


ber of  the  same  frame  at  the  same  sir- 
mark.  Now  suppose  the  siding  size  of 
the  timber  to  be  10  inches,  it  must  be 
apparent  that  we  could  not  accomplish 
our  purpose  of  obtaining  the  bevel  of 
both  timbers  by  taking  all  the  bevel  of 
the  one  timber,  and  reversing  this  bevel 
for  the  other  timber  of  the  same  frame 
and  at  the  same  sirmark.  Hence  it 
will  be  observed,  that  the  smaller  the 
distance  taken  across  the  line,  the  near- 
er will  the  bevel  apply  to  the  opposite 
limber  of  the  frame  when  reversed. 
Thus  we  may  observe,  that  six  inches 
may  be  adopted  instead  often  from  the 
moulding-edge,  or  face  side  of  the  tim- 
ber, (and  we  have  applied  this  method 
to  vessels  where  even  three  inches  were 
an  abundance,)  the  smaller  the  circum- 
ference of  the  curve,  the  smaller  tin- 
space  required  for  reversing  the  bevel. 
It  will  be  observed,  that  this  method, 
although  far  preferable  to  the  one  he- 
fore  delineated,  in  connection  with 
cants  by  water-lines,  is  only  applicable 
where  there  are  no  chocks,  or  where 
the  chocks  are  small.  The  nut  hod 
we  have  referred  to  is  not  confined  to 
water-line  cants,  but  is  equally  applica- 
ble here.  Having  found  at  what  dis- 
tance from  the  face  the  bevel  may  he 
taken,  in  order  that  it  may  be  reversed, 
we  may  strike  up  a  parallel  line  to  the 
joint  line.  As  we  before  remarked,  the 
distance  is  consequent  upon  the  bevel 


254 


MARINE    AND    NAVAL    ARCHITECTURE. 


when  reversed,  as  the  design  is  that 
the  bevel  shall  apply  equally  well  to 
both  timbers  of  the  frame.  If  for  ex- 
ample, the  frame  upon  which  we  are 
determining  the  bevel,  be  in  the  after- 
body, it  follows  that  we  are  determin- 
ing by  the  bevel  taken  from  the  forward 
timber  say  six  inches  from  the  face  ; 
that  is  to  say  :  how  much  bevel  has 
the  forward  timber,  provided  it  was 
sided  but  six  inches  ?  This  being  de- 
termined, set  the  bevel  to  the  amount ; 
apply  it  to  the  timber,  or  to  its  space 
on  the  floor,  which  is  the  same  thing  ; 
ascertain  how  much  it  would  take  off 
the  forward  or  bevelling  edge  ;  reverse 
the  bevel,  and  apply  it  to  the  space  that 
would  be  occupied  by  the  after  timber  ; 
and  if  it  woidd  require  more  to  be  taken 
off  the  bevelling  edge  than  off  the  for- 
ward timber,  or  less,  we  evidently  bevel 
too  much  or  too  little  on  the  forward 
timber  ;  that  is  to  say:  six  inches  is 
too  much,  or  not  enough.  We  may 
thus  arrange  or  adjust  the  bevel  by 
applying  the  straight  edge  in  several 
places  or  parts  of  the  body  in  which 
we  may  be  at  work. 

It  should  not  be  forgotten  to  apply 
the  batten  both  ways  in  taking  off  the 
bevelling  edges  from  the  half-breadth 
plan,  in  the  same  manner  that  we  did 
the  moulding-edge,  inasmuch  as  this 
edge,  or  the  assumed  six  inches  requires 
its  ov\  n  sir  mark  on  the  diagonal :   what- 


ever the  rising  of  the  diagonal  as  wc 
approach  the  centre  may  be,  it  must 
be  noted,  and  the  sirmark  raised  ac- 
cordingly. Thus  we  discover  thai  each 
setting-off  as  a  hall-breadth  must  be 
applied  to  its  own  sirmark.  When  wc 
have  found  a  distance  that  will  furnish 
not  only  the  bevel  of  the  timber  from 
which  it  was  taken,  or  for  the  halt- 
frame  to  which  it  belongs,  but  being 
reversed,  will  apply  equally  well  to  the 
opposite  timber,  we  may  take  off  as 
described,  first  the  rise  of  the  sirmark, 
which  must  be  carried  out  level  in  the 
body-plan,  then  the  half-breadth  on 
this  level  line  ;  the  bevelling  edges  may 
be  swept  in  the  body-plan  with  white 
chalk;  after  which,  a  bevelling-board 
may  be  prepared  to  the  size  or  width 
we  have  determined  upon,  as  the  given 
distance  in  which  the  bevel  is  obtained. 
We  may  remark,  that  in  all  probability 
this  would  in  no  case  be  less  than  two 
and  a  half  inches,  or  more  than  six. 
The  larger  the  vessel,  that  is,  at  the 
same  time  full,  the  nearer  we  approach 
the  latter  size  or  number,  while  on  the 
other  hand,  the  small  full  sloop  or 
schooner  would  not  require  more  than 
two  and  a  half  inches.  The  principle 
lies  just  here — the  mean  of  a  given  dis- 
tance on  the  circumference  of  a  barrel-' 
hoop  will  be  more  than  on  that  of  a  hogs- 
head-hoop in  the  same  distance.  This- 
seems   to   be   paradoxical  at   the    first 


MARINE    AND    NAVAL    ARCHITECTURE. 


255 


glance,  inasmuch  as  the  quick  curve 
requires  but  a  small  setting-off;  and 
yet  a  vessel  still  fuller  may  require  less. 
This  is  very  possible  on  account  of  the 
great  difference  in  the  size  of  the  ves- 
sels. On  the  small  vessel  the  timber 
may  be  sided  only  six  inches,  while  on 
the  large  ship  it  may  be  sided  ten  inches 
or  more.  Thus  it  will  be  seen,  that  if 
we  took  as  much  for  the  small  vessel, 
though  even  less  round  than  the  lines 
of  the  large  ship,  we  would  have  the 
whole  size  of  the  timber.  There  can 
no  rule  be  given  that  will  apply  in  every 
case ;  the  judgment  must  determine 
the  distance  to  be  taken,  let  the  dis- 
tance be  what  it  may.  The  be  veiling- 
board  must  be  of  the  same  width,  hav- 
ing the  diagonals  and  sheer-lines  in  the 
cant  as  well  as  square  body-plan  ;  they 
are  equally  as  applicable  for  sirmarks 
or  bevelling  spots,  and  may  be  marked 
on  the  moulds,  remembering  that  the 
mould  is  to  be  made  to  the  blue  or  red 
line,  and  that  the  spot  where  the  level 
line  crosses  the  moulding-edge  is  the 
sirmark  to  be  marked  on  the  mould  ; 
the  diagonal  is  found  to  be(the  distance 
between  the  line  levelled  out,  showing 
the  same  as  it  now  is,)above  its  former 
place  caused  by  swinging  the  frame 
round  from  a  square,  or  consequent 
upon  the  frame  having  been  swung 
round  to  its  place.  Thus  the  floor  we 
perceive  will  not  regulate  the  frames  to 


their  proper  places,  like  the  draft;  they 
treat  all  frames  alike,  keeping  them  all 
on  a  plane;  hence  it  is  important  that 
those  discrepancies  should  be  noted  and 
attended  to. 

Having  shown  the  manner  of  laying- 
down  the  cants  by  diagonals,  and  pre- 
paring the  bevelling-board,  we  will  next 
notice  the  manner  of  taking  off  the 
bevelling  of  the  cants.  It  will  be  ob- 
served, that  we  take  the  bevel  from 
the  after  timber  of  the  frame  if  in  the 
fore-cant  body-plan,  and  from  the  for- 
ward timber  if  in  the  after-cant  body. 
Hence  it  is  quite  clear  that  whether 
the  bevel  be  standing  or  under,  it  is  the 
timber  we  have  described,  and  is  known 
by  the  body  it  is  in,  whether  forward 
or  aft;  and  if  it  be  the  forward  timber 
of  the  after-body,  and  bevels  standing 
as  they  usually  do,  it  then  also  follows 
that  its  mate  or  the  opposite  timber  of 
the  frame  bevels  under  ;  and  if  we  car- 
ry out  the  same  order  in  the  bevels  that 
is  usually  carried  out  in  the  futtocks, 
viz.,  to  reverse  them,  as  we  have  shown 
we  may  apply  the  bevel  from  the  left 
hand,  or  what  is  the  same  thing,  take 
off  the  opening  between  the  red  or  blue 
and  white  line,  and  apply  it  on  the  right 
of  the  board,  when  it  is  placed  square 
before  us,  cither  above  or  below  a 
square  line,  as  the  bevel  may  demand. ' 
If  the  white  line  is  without,  the  bevel 
is   standing  from   a   square    the   whole 


25G 


MARINE  AND    NAVAL    ARC  H  ITE  CT  D  RE. 


space  between  the  lines  and  the  same 
amount  under:  if  as  much  within  a 
square,  these  bevels  may  be  transferred 
to  a  wider  board  for  use  in  the  yard, 
and  in  this  case,  it  will  be  readily  per- 
ceived, that  we  require  but  one  board 
in  the  place  of  two:  the  same  board 
that  shows  standing-  bevels  when  taken 
from  the  left  hand,  will  show  under 
bevels  when  taken  from  the  right.  One 
of  the  principal  advantages  of  this  mode 
(is  the  spacing  off  the  body-plan  on 
but  a  single  side,  and  reversing  the 
bevel  for  the  opposite  timber,)  is  found 
in  our  having  but  one  bevelling  board 
for  the  fore-body,  and  another  for  the 
after-body;  while  by  the  former  method 
of  laying  down  the  bevel  in  the  full  size 
of  the  timber,  we  require  two  boards 
for  each  cant  body ;  another  advantage 
is  found  in  the  fact,  that  the  latter  is 
done  in  less  time,  and  is  less  liable  to 
mistakes  by  the  workmen.  Having  but 
one  board  with  as  many  sets  of  bevels 
parceled  out  as  there  are  diagonals  and 
sheer-lines,  all  named  in  regular  order, 
commencing  either  above  or  below, 
with  the  bevel  against  the  side  of  the 
dead-wood,  and  then  follows  in  regular 
order  1st,  2nd,  3rd,  4th  and  5th  diago- 
nals, and  more  if  required ;  next  to 
these  we  have  1st,  2nd,  3rd,  and  4th 
breadths.  Under  these  several  heads 
are  found  all  the  cant  bevels  of  one  body; 
and  it  is  plain,  that  if  there  are  but  six 


cants,  there  will  be  but  six  bevels  un- 
der each  ofthose  heads.  The  bevel  <>f 
the  heel  of  the  timber  against  the  dead- 
wood  is  taken  from  the  hall-breadth 
plan  by  applying  the  stock  of  the  bevel 
bv  the  straight  line  showing  the  cant, 
while  the  tongue  was  applied  againsl 
the  side  line,  which  represents  the  dead- 
wood.  If  we  have  tapered  chocks,  we1 
must  see  that  the  bevel  is  taken  from 
the  moulding-edge,  because  that  being 
the  face  of  the  timber,  is  the  side  on 
which  it  is  applied. 

The  subject  of  bevelling  the  cants 
being  finished,  we  may  find  this  an  ap- 
propriate place  for  giving  expositions 
of  the  manner  of  bevelling  the  square 
body,  although  most  European  archi- 
tects defer  this  important,- but  simple 
operation,  until  after  the  moulds  are 
made.  This  is  evidently  wrong  ;  as  it 
is  but  too  apparent  that  the  lines  be- 
come dim,  and  we  fail  to  find  that 
sharpness  requisite  to  take  the  bevels 
correctly. 

It  must  be  quite  clear  to  the  discern- 
ing mind  that  it  is  the  bevelling  of  the 
timbers  composing  the  frame  of  the 
vessel  that  gives  her  shape  and  form, 
without  which  she  must  of  necessity  be 
stamped  with  a  manifest  sameness; 
the  ends  must  of  necessity  be  what  the 
middle  is.  But  by  starting  from  the 
dead-flat  frame,  and  causing  the  one 
timber  to  foil  without  a  square,  and  its 


MARINE    AND    NAVAL    ARCHITECTURE. 


257 


companion  of  the  same  frame  to  fall 
within,  we  are  enabled  to  give  form  or 
shape  to  the  vessel,  and  expand,  con- 
tract, or  continue  her  in  any  manner 
we  please.  The  bevels,  as  a  whole, 
are  obtained  from  different  parts  of  the 
floor,  but  principally  from  the  body- 
plan,  and  should  be  taken  in  all  cases 
before  making  the  moulds,  for  the  rea- 
sons already  shown.  In  addition  to 
another  fact,  viz.,  that  the  moulds  are 
of  little  service  without  the  bevels ;  for 
the  bevellings  of  the  square  body  we 
may  prepare  two  copy  boards,  which 
•should  be  left  in  the  loft ;  they  may  be 
of  the  usual  width,  eight  or  nine  inches, 
and  long  enough  to  take  on  all  the 
bevels  from  the  floor  ;  from  eight  to  ten 
feet  will  be  quite  sufficient  ;  the  outer 
edges  of  these  boards  must  now  be 
placed  a  parallel  distance  apart,  equal 
to  the  distance  from  the  joint  of  one 
frame  to  the  joint  of  the  next ;  and  in 
that  position  they  may  be  battened  on 
the  ends,  and  a  diagonal  brace  on  the 
lower  side,  to  prevent  vibration.  Our 
frame  now  is  supposed  to  be  the  exact 
distance  between  the  two  outer  edges 
that  the  floor  timbers  are  placed  apart 
from  face  to  face,  or  what  is  usually 
termed  the  room  and  space,  which 
means  neither  more  nor  less  than  the 
room  between  the  timbers  and  the  space 
occupied  by  the  timbers.  Commence 
at  the  head  of  the  board  by  drawing  a 


line  square  across  the  board,  then  take 
a  thin-edged  batten,  and  from  the  fore- 
body  plan  at  every  sheer-line  and  diago- 
nal line  in  their  regular  order,  take  the 
shortest  distance  from  the  forward  to 
the  next  adjoining  square  frame  ;  this 
may  be  regarded  as  both  the  standing 
and  under  bevellings,  (assuming  that  we 
are  to  have  but  one  set  of  bevels  for 
both  timbers.)  For  example,  suppose 
the  forward  square  frame  be  Z  :  the 
distance  from  Z  to  Y  is  the  bevel  of  Z 
on  any  line  we  may  choose  to  try  the 
opening  and  the  bevel,  so  with  Y  ;  the 
distance  from  that  frame  to  X  is  the 
bevel  ofY,  so  of  W  ;  the  distance  from 
that  frame  to  X  is  the  bevel  of  X,  and 
this  may  be  continued  on  to  the  dead- 
flat  frame  on  the  same  line  on  which 
we  began ;  that  is  to  say,  if  we  began 
with  the  first  diagonal  in  the  fore-body, 
continue  with  that  diagonal  and  in  the 
same  body,  until  we  complete  the  line 
we  were  upon  ;  it  may  not  be  judicious 
to  take  off*  all  the  spaces  on  the  batten. 
before  transferring  them  to  the  copy- 
board.  The  manner  of  applying  them 
will  be  found  in  the  following  :  from 
and  below  the  square  line  across  both 
boards,  set  ofF  these  graduations  of 
every  timber,  remembering  the  bevels 
are  to  be  severally  named  on  the  board 
as  the  timbers  are  in  the  body-plan  ; 
having  the  spots  on  the  edge  of  the 
board,  we  may  tack  a  small  nail  in  the 


33 


25S 


MARINE    AND    NAVAL    ARCHITECTURE 


opposite  edge  of  the  opposite  board, 
and  in  the  square  line  ;  thus  it  will  be 
perceived,  that  the  nail  and  the  marks 
on  the  edge  of  the  opposite  board  are 
the  whole  room  and  space  apart.  We 
now  take  a  thin  straight  edge,  and 
holding  one  edge  to  the  nail  on  one 
side,  and  to  the  first  spot  below  the 
square  line  on  the  other,  we  mark  with 
a  sharp  pencil  across  the  board  on 
which  the  spots  were  made  only ;  we 
then  drop  the  straight  edge  to  the  next 
spot ;  the  end  at  the  nail  remaining 
stationary,  until  all  the  bevels  belong- 
ing to  this  diagonal  are  taken  off.  We 
then  square  another  line  across  imme- 
Jiately  below  the  bevels  of  the  first  di- 
agonal, and  commence  on  the  second 
diagonal  in  the  same  manner  as  the 
first  were  taken,  giving  each  set  of 
bevels  their  proper  name  as  we  ad- 
vance ;  the  sheer-lines  are  taken  in  the 
same  manner,  all  of  which  follow  on  in 
succession,  are  marked  across  the  one 
board  only,  and  which  will  complete 
the  bevels  of  the  square  fore-body. 
We  should  have  enough  space  left  to 
transfer  the  fore-body  cant  bevels,  bar- 
pen  bevels,  and  knight-head  bevels  to 
this  same  board.  We  may  reverse  the 
order  for  the  after-body ;  that  is,  the 
nail  will  come  on  the  side  on  which 
the  bevels  have  been  applied  in  the 
square  line  as  before,  and  taken  off  and 
applied  in  the  same  manner  as  the  fore- 


body,  remembering  to  begin  aft.  as 
the  after  opening  belongs  to  the  after 
frame  on  this  board  ;  also  the  bevels  of 
the  after  cants,  harpens,  and  transoms 
should  find  a  place,  inasmuch  as  a  Copy 
of  every  bevel  should  be  kept  until  the 
frame  is  all  worked  out.  The  bevel- 
lings  of  the  seats  of  the  floors  may  be 
obtained  from  the  sheer-plan,  as  shown 
in  Plate  8,  by  applying  the  stock  of  the 
bevel  against  the  line  showing  the  face 
of  the  floor,  and  the  tongue  extending 
along  the  line  representing  their  seats  ; 
those  bevels  need  not  go  on  the  copy- 
board,  inasmuch  as  they  are  not  want- 
ed after  the  floors  are  worked  out. 

It  was  formerly  the  custom  in  Eng- 
land, and  is  still  adhered  to  in  some 
parts  of  Europe,  to  take  the  bevels  from 
the  half-breadth  plan  by  setting  ■off  the 
size  of  the  timber  each  side  of  the  joint 
of  the  frame,  and  taking  off  the  within 
or  without  a  square  the  bevel  gave  ; 
this  practice  is  not  only  tedious,  but  it 
does  not  give  the  correct  bevel,  inas- 
much as  the  lines,  even  though  diago- 
nals, do  not  cut  the  frames  square  from 
their  moulding-edges  in  all  cases,  nor 
can  they  be  so  arranged  as  to  accom- 
plish this. 

The  present  practice  in  England  is 
as  follows :  to  take  the  opening  be- 
tween the  two  last  square  frames  for 
the  standing  bevel,  and  the  intermediate 
spaces  for  the  under   bevels  ;   that   is, 


MARINE    AND    NAVAL    ARCHITECTURE 


259 


suppose,  as  we  have  assumed,  Z  to  be 
the  forward  square  frame,  then  from 
Z  to  Y  would  be  the  standing  bevel  of 
Z  ;  its  under  bevel,  or  the  under  bevels 
of  Z,  would  be  obtained  by  finding  the 
distance  to  the  next  square  frame  for- 
ward ;  the  spot  for  which  must  be  taken 
from  the  half-breadth  plan,  inasmuch 
as  the  frame  is  not  swept  in  ;  thus  for 
the  standing  bevels  we  take  the  open- 
ings from  forward  in  the  fore-body,  and 
from  aft  in  the  after-body;  while  for  the 
under  bevellings,  we  begin  at  the  dead- 
flat  frame,  and  proceed  aft  and  forward, 
talcing  the  graduations  in  their  regular 
order,  setting  off  these  graduations 
for  the  under,  below  the  square  line, 
and  those  for  the  standing  bevels  above 
it ;  from  these  different  spots,  lines  are 
drawn  to  the  opposite  board,  as  Ave 
have  shown.  This  of  course  contem- 
plates two  sets  of  bevelling-boards  ;  it 
is  the  most  correct  method  that  has 
ever  yet  been  adopted.  The  difference, 
however,  between  the  manner  we  have 
shown  is  inconsiderable,  and  would  not 
compensate  for  the  extra  work,  it  can 
only  be  perceived  at  the  extremities, 
and  is  so  small  that  it  is  not  worthy  of 
notice.  The  two  sets  of  bevelling- 
boards  referred  to,  would  be  distinguish- 
ed by  being  marked  for  opposite  sides 
of  the  frame;  one  board  for  the  bevel- 
lings  of  the  floors,  second  futtoeks, 
fourth    futtoeks,   and    half  top-timber 


on  one  side  of  the  frames  of  the  fore- 
body,  and  the  other  board  for  the 
bevels  of  the  first  and  third  futtoeks 
and  top-timber  of  the  square  frames 
of  the  same  body.  Hence  it  is  quite 
manifest  that  four  boards  would  be  re- 
quisite for  the  square  body,  inasmuch 
as  two  more  boards  would  be  required 
for  the  after-body,  making  four  bevel- 
ling-boards for  the  square  body  ;  and 
we  may  add,  that  this  is  the  practice 
to  some  extent  in  the  United  States, 
both  of  taking  off  the  bevels  and  of 
distributing  them  on  the  board  ;  but 
we  think  it  unnecessary  to  have  more 
than  two  bevelling-boards  for  the  square 
body,  commencing  with  the  first  diago- 
nal, and  following  on  in  succession  un- 
til we  reach  the  rail-height  be  veilings. 
Thev  should  be  marked  on  the  board 
from  the  copy-board  in  the  following 
manner:  first,  at  the  head  name  the 
board,  that  it  may  be  known  ;  then 
mark  a  square  line  across,  just  below 
the  name,  marking  this  cluster  of  bevels 
first  diagonal ;  from  this  square  line  set 
off  downward  on  the  left-hand  m\gti  of 
the  board,  spots  about  one-quarter  of 
an  inch  apart.  AVe  now  apply  the 
bevels  in  regular  succession;  tin;  square 
mark  will  be  the  ©,  and  whether  in  the 
fore  or  after-body,  we  continue  on  un- 
til we  reach  the  highest  number  or  let- 
ter, as  tin-  ease  may  be,  in  the  alpha- 
bet, or  in  the  numbered  square  body. 


2G0 


MARINE    ANJ)    NAVAL    ARCHITECTURE 


Thus  we  have  all  the  bevels  of  the 
square  body  at  the  first  diagonal  to- 
gether ;  those  on  the  floor  side  of  the 
frame  are  taken  from  the  left  hand ; 
and  those  from  the  first  futtock  side 
of  the  frame  are  taken  from  the  right 
hand.  The  same  may  be  said  of  the 
second  and  all  the  remaining  diagonals 
and  sheer-lines  or  breadths. 

It  has  been  the  custom  in  the  Navy 
yards  to  have  a  bevelling-board,not  only 
for  the  standing  bevels  and  another  for 
the  under  bevcllings,  but  one  for  each 
class  of  futtocks,  another  for  the  floors, 
another  for  the  top-timbers,  and  indeed 
for  every  change  of  name  in  bevels, 
another  board  was  deemed  necessary. 
Hence  it  is  not  at  all  difficult  to  imag- 
ine that  it  took  a  good  share  of  the 
time  to  keep  the  boards  at  hand  that 
might  be  required.  In  some  private 
yards  one  set  of  bevelling-boards  are 
used,  as  we  have  described,  for  the  un- 
der bevellings,  and  they  are  arranged 
just  as  we  have  described  another  set 
for  the  standing  bevels  in  the  same  or- 
der. It  is  seldom  the  case,  however, 
that  two  set  of  boards  are  used,  unless 
two  sets  of  bevels  are  taken. 

Before  leaving  the  subject  of  bevel- 
lings,  in  connection  with  the  square 
body,  we  will  endeavor  to  show  the 
manner  of  making  and  taking  the  bevel 
of  the  harpens.  It  will  be  observed, 
that  the  harpens  are  pieces  of  plank 


scarfed  together,  and  worked  out  in 
the  form  of  the  bow  at  one  of  the  sheer- 
lines,  extending  from  the  stem  or 
knight-heads,  where  they  are  fastened 
across  the  cants  to  the  square  frames ; 
they  are  placed  with  their  upper  edges 
to  the  sirmarks  on  the  frames,  and  their 
extent  on  the  square  frames  is  usually 
three  or  four  frames;  their  principal 
use  is  to  regulate  the  cants,  and  give 
them  a  landing  when  raised,  inasmuch 
as  they  are  not  a  part  and  parcel  of  t  lie 
ship  ;  they  are  not  made  very  smooth  ; 
their  top-side,  however,  should  be  fair 
and  out  of  winde  at  every  cant  and 
square  frame,  in  order  that  the  bevel 
may  be  applied  correctly;  the  moulds 
for  the  harpens  are  made  from  the  half- 
breadth  plan;  few  large  ships  have  less 
than  three  harpens  forward,  and  three 
aft.  Of  late  years  the  custom  has  pre- 
vailed of  making  a  harpen  at  the  load- 
line  of  flotation,  and,  as  a  consequence, 
the  line  has  become  a  sirmark  for  this 
express  purpose,  and  is  usually  sawed 
in  on  the  corner  of  one  of  the  timbers 
of  the  frame  in  the  direction  in  which 
it  points  across  the  ship,  in  order  that 
it  may  be  known  from  other  sirmarks 
that  are  put  on  for  other  purposes.  It 
is  optional  with  the  builder  at  which 
of  the  sheer-lines  besides  that  of  the 
rail  that  he  will  place  his  harpens  for- 
ward. If  the  ship  has  a  square  stern, 
he  will  require  none    aft   at   the    rail ; 


MARINE    AND   NAVAL    ARCHITECTURE. 


261 


there  is  usually  one  placed  at  the  first 
breadth  aft,  and  the  one  below  at  the 
load-line  which  is  continued  around  the 
ship.  It  is  not,  however,  worked  out  to 
the  shape  of  the  ship  farther  than  the 
forward  and  after-pieces,  or  until  it  is 
extended  so  far  that  a  ribband  may  be 
bent  the  remaining  distance  midships. 
The  bevels  of  the  harpens  are  taken  in 
the  following  manner  :  apply  the  stock 
of  the  bevel  to  a  level  line  at  the  height 
at  which  the  mould  is  made  in  the 
body-plan.  The  tongue  should  then 
extend  downward  with  the  frame,  which 
on  the  bow  will  give  a  standing  bevel ; 
this  operation  is  performed  on  every 
cant  frame,  and  on  the  square  frames 
as  far  as  they  extend.  It  should  be 
observed,  that  the  harpen  mould  should 
be  made  with  its  hollow  edge,  or  inside 
to  the  line  in  the  half-breadth,  inas- 
much as  it  extends  outside  of  the  mould- 
ing-edges of  all  the  frames,  and  is  fast- 
ened to  the  frames  to  keep  them  in 
their  places.  The  mould  should  also 
have  the  station  and  direction  of  all 
the  cants  and  square  frames,  as  far  as 
it  extends,  marked  on  it. 

We  have  said  that  the  harpens  were 
secured  to  the  knight-heads  forward, 
this  leads  us  to  a  consideration  of  the 
location  and  design  of  those  timbers. 
It  will  be  discovered  by  the  attentive 
observer,  that  the  forward  cants  are 
close  together  on  the   stem,  and    ex- 


tend quite  high  up  the  same  at  their 
heels,  notwithstanding  their  heads  may 
be  farther  apart  than  at  other  parts  of 
the  ship ;  hence  it  may  be  fairly  in- 
ferred that  another  arrangement  is  ne- 
cessary to  give  that  security  to  the  bow 
above  water  that  is  required  ;  the 
knight-heads  and  hawse-pieces  were 
designed  to  furnish  that  security.  We 
have  shown  in  a  former  chapter  that 
the  dead-wood  should  be  of  sufficient 
depth  or  size  to  cover  the  heels  of  the 
cants,  and  we  will  now  add,  that  the 
dead-wood  forms  a  continuous  line  in 
connection  with  the  keelsons,  from  the 
lower  side  of  the  lower  transom  to  the 
lower  side  of  the  bow-sprit ;  the  piece 
of  timber,  however,  that  continues  the 
dead-wood  from  the  bow-sprit  down  to 
the  stemson,  is  called  the  apron  ;  this 
piece  of  timber  is  bounded  on  its  for- 
ward side  by  the  inside  of  the  stem, 
and  when  the  stem  is  in  two  pieces,  it 
is  designed  to  cover  the  scarf,  and  ex- 
tend below  that  point  a  sufficient  dis- 
tance to  add  the  necessary  strength  ;  its 
siding  size  should  be  as  large  as  that 
of  the  bow-sprit,  or  within  one  or  two 
inches  of  that  size,  when  it  can  be  ob- 
tained, for  several  reasons,  which  shall 
follow  in  their  place;  when  this  cannot 
be  accomplished,  we  may  place  a  cho 
on  each  side  to  furnish  the  required 
size1 ;  the  fore  and  all  size  of  the  apron 
is  determined  by  what  the  cants  would 


202 


MARINE    AND    NAVAL    ARCHITECTURE. 


measure  in  the  direction  of  the  sides  of 
the  apron,  added  to  which  should  be 
the  thickness  of  the  ceiling.  This,  it 
will  be  observed,  would  cause  the  ceil- 
ing to  butt  against  the  apron,  just  as 
the  plank  outside  butts  against  the  stem, 
with  this  exception,  however,  there 
must  be  no  rabbet.  It  is  seldom  that 
the  apron  will  hold  this  size,  unless  the 
ship  is  very  full,  although  it  should  in 
all  ships  be  carried  down  at  this  size 
as  low  as  the  lower  deck  ;  below  that 
point  the  clamps  and  ceiling  may  ex- 
tend over  the  after  side  of  the  apron, 
and  butt  in  the  centre  ;  and  the  only 
reason  in  many  cases  why  the  apron 
does  not  extend  as  far  aft  as  we  have 
said  that  it  should  extend,  is  found  in 
the  fact  that  the  scantling  size  of  the 
cants  is  too  large.  Our  principal  rea- 
son for  advocating  a  larger  apron  than 
the  usual  size  is,  that  we  have  discoun- 
tenanced large  stems  the  fore  and 
aft  way,  believing  them  to  be  injurious 
to  the  performance,  as  well  as  detri- 
mental to  the  ship  when  a  cut-water 
is  to  be  appended,  and  a  part  of  what 
we  would  take  off  the  stem,  we  would 
add  to  the  apron  ;  there  is  no  mould 
required  for  this  timber,  the  stem 
mould  being  quite  sufficient.  The 
sides  are  parallel,  and  of  course  stand 
fore  and  aft ;  the  after  side  is  assumed 
to  be  square  from  either  of  the  two 
sides.      It  is  on  the  sides   of  the  apron 


that  the  knight-heads  are  placed,  ex- 
tending in  some  cases  from  its  lowest 
point,  (where  it  is  cut  off  against  the 
forward  cant)  to  the  rail,  and  often  is 
left  a  foot  or  more  above  the  rail  ;  as 
a  consequence,  its  sides  must  stand  fore 
and  aft,  inasmuch  as  those  of  the  apron 
does ;  and  faying  against  the  apron, 
must  of  necessity  stand  in  line  fore 
and  aft,  and  as  the  scantling  of  the 
cant  timbers,  as  well  as  all  other  parts 
of  a  ship's  frame,  is  set  off  on  a  square, 
and  not  on  the  face  of  the  limber,  (un- 
less the  timber  bevel  but  little,)  it  iol- 
lows  that  the  .  moulding  size  of  the 
knight-heads,  or  their  scantling  size1, 
should  also  be  measured  on  a  square, 
and  compare  in  that  particular  with 
the  adjacent  timbers  forming  the  cant 
frames;  from  the  head  of  these  timbers 
downward  for  about  two  strakes  below 
the  head  of  the  stem,  the  scantling 
size  above  this  point  should  be  in- 
creased both  inside  and  out,  this  addi- 
tion should  amount  to  the  thickness  of 
the  plank  forming  the  bulwarks  ;  the 
object  of  this  addition  is  to  avoid  the 
ending  of  the  plank  in  the  bed  of  the 
bow-sprit,  by  their  butting  on  the  mid- 
dle of  the  knight-head  and  showing 
their  butts,  rather  than  running  across 
the  timber. 

It  must  be  quite  apparent,  that  if  the 
apron  is  sided  more  than  the  siding  size 
of  the  stem,  that  the  moulding-edge  of 


MARINE   AND    NAVAL    ARCHITECTURE. 


263 


the  knight-head  must  be  of  different 
form  from  that  of  the  inside  of  the 
stem.  In  order  to  obtain  the  form  of 
the  moulding-edge  of  the  knight-head, 
we  must  set  off  in  the  half-breadth 
plan  lines  parallel  with  the  side-line 
representing-  the  size  of  this  timber,  after 
knowing  how  much  it  will  side  ;  there 
is  no  objection  to  its  being-  sided  larger 
than  the  frame,  inasmuch  as  it  affords 
room  for  spreading-  the  fastening,  and 
for  securing  the  butts.  Having  deter- 
mined upon  their  thwartship  siz*?,  we 
may  show  them  in  the  half-breadth  in 
the  manner  described.  We  have  said 
that  chocks  were  objectionable  when 
the  siding  size  of  the  apron  was  not  all 
that  we  could  desire  ;  it  is  well  known 
that  a  large  amount  of  fastening  finds 
its  way  here,  and  if  the  holding  surface 
is  made  up  of  several  pieces,  the  fast- 
ening finds  its  way  into  those  joints 
by  splitting  off  the  edge  of  the  chocks, 
and  holds  less  than  if  in  one  piece. 
The  sides  of  the  knight-head  being  thus 
shown,  it  will  be  seen  that  the  mould-: 
ing  edge  is  formed  by  the  lines  running 
across  their  sides  ;  these  crossings  of 
the  sheer  and  water-lines,  if  squared  up 
to  their  corresponding  lines  in  the  sheer- 
plan,  will  show  the  form  of  the  mould- 
ing-edge ;  the  bevelling-edge  is  obtain- 
ed in  the  same  manner  ;  the  lines  in 
the  half-breadth  showing  the  siding  size 
of  the  knight-head,  may  extend  to  the 


forward  cant,  which  will  cut  off  the 
heel  of  the  knight-head  whatever  the 
siding  size  of  the  cant  timber  may  be 
shorter  than  the  cant  line  would  »ive 
in  the  half-breadth.  We  may  obtain 
this  ending  of  the  knight-head  in  the 
following  manner:  set  off  in  the  half- 
breadth,  the  siding  size  of  the  forward 
cant  timber,  and  mark  it  across  the 
same;  it  then  follows  that  the  knight- 
head  cuts  off  against  this  timber;  the 
intersection  of  this  line  with  the  side 
line  may  now  be  squared  up  to  the 
sheer-plan,  which  will  show  not  only 
the  length  of  the  knight-head,  but  that 
its  heel  cuts  square  from  the  base;  it 
will  be  observed  that  the  timber  will  be 
shorter  if  the  apron  is  sided  more  than 
the  stem,  inasmuch  as  the  cant  of  the 
frame  inclines  it  farther  forward  at  the 
head  than  at  the  heel,  and  tends  to  short- 
en all  the  timbers  that  come  within  the 
intermediate  space.  The  bevel  of  the 
heel  is  obtained  by  applying  the  stock 
of  the  bevel  against  the  side  line  in  the 
half-breadth  plan,  the  heel  of  which 
must  be  forward ;  we  then  close  the 
bevel  until  the  tongue  ranges  out-board 
and  with  the  side  of  the  cant  ;  this  is 
the  bevel  of  the  heel  of  the  knight-head, 
to  be  applied  from  the  moulding  side 
or  face  of  the  timber,  the  bevel  or  an- 
gle the  other  way,  having  been  shown 
to  be  at  right  angles  with  the  base-line  : 
the   bevels  of  the  outside,  or  what  is 


264 


MARINE   AND    NAVAL    ARCHITECTURE. 


usually  termed  the  back  of  this  timber, 
are  obtained  by  applying  the  stock  of 
the  bevel  against  the  line  showing  the 
side  of  the  timber*  and  the  tongue  out- 
board to  the  line  at  which  the  bevel  is 
required  ;  or  the  bevel  may  be  taken 
by  applying  a  square  as  in  the  place  of 
the  bevel,  the  tongue  of  which  must  be 
placed  at  the  intersection  of  the  out- 
board side  of  knight-head,  with  the 
line  upon  which  the  bevel  is  required  ; 
then  measure  the  distance  from  the 
square  to  the  moulding-edge  of  the 
knight-head  ;  but  the  most  simple,  and 
we  think  the  most  appropriate  way  of 
obtaining  the  bevels,  is  to  lay  down 
both  edges  of  the  timber,  and  we  have 
the  bevel  any  where,  and  may  take  it 
off  by  measuring  the  distance  the  out- 
board edge  falls  aft  of  the  moulding-edge 
in  the  siding  size  laid  down  ;  as  a  con- 
sequence, the  knight-head  bevels  under, 
just  that  distance.  On  very  sharp  ves- 
sels it  may  be  found  advantageous  to 
cant  the  knight-heads,  (for  the  reason,) 
that  a  smaller  piece  of  timber  will  make 
them.  The  operation  of  laying  down 
canted  knight-heads  is  very  similar  to 
that  of  those  already  described  ;  and 
when  this  method  is  adopted,  we  should 
show  in  the  sheer-plan  the  form  of  the 
fore  side  or  bevelling  edge  of  the  cant 
timber,  by  first  marking  its  size  in  the 
hall-breadth  plan,  forward  of  the  joint 
of  the  frame;  we  may  then  square  up 


the  spots  at  which  this  line  crosses  the 
several  water  and  sheer-lines,  mark  in 
the  line  by  those  spots,  and  we  have 
the  ending  of  the  knight-heads  in  the 
sheer-plan  also  ;  this,  however,  is  not 
absolutely  necessary  in  the  case  of 
canted  knight-heads  more  than  fore  and 
aft  ones,  but  it  may  serve  to  make  the 
subject  more  clear  by  exhibiting  it  in 
more  than  one  aspect  ;  the  cant  of  the 
knight-head  may  be  determined  in  the 
half-breadth  plan,  remembering  that 
tjie  heeLmust  taper,  else  the  head  will 
not  come  up  to  the  apron  ;  this,  it  will 
be  observed,  would  be  an  objectionable 
feature,  as  we  have  shown,  on  account 
of  the  fastening  in  the  wood-ends  of  the 
outside  plank;  the  more  cant  we  have 
the  more  taper  will  of  necessity  be  re-  ^ 
quired,  unless  the  bow  be  quite  straight, 
at  least  the  length  of  the  knight-head  ; 
this  renders  the  operation  of  laying 
them  down  precisely  the  same  as  that 
of  the  tapered  chocks  in  the  cants.  I 
We  may  show  both  edges  in  the  half- 
breadth  plan  with  any  cant  we  please  ;1 
square  up  the  spots  at  which  they  in-  | 
tersect  the  sheer,  horizontal  ribbands, 
and  water-lines  in  the  sheer-plan  ; 
sweep  in  the  curve  those  spots  furnish, 
and  we  have  their  thwartship  view  in 
the  sheer-plan  as  though  they  were 
cants,  which  they  virtually  are;  the 
shape  on  the  face  of  canted  knight-  r 
heads  is  obtained  in  the  same  manner 


MARINE    AND    NAVAL    ARCHITECTURE, 


265 


ns  a  cant  is,  by  taking  the  distance  in 
the  half-breadth  plan  from  the  middle- 
line  on  the  line  showing  their  face  to 
the  crossing  of  the  several  sheer  and 
water-lines  ;  these  settings-off  are  ap- 
plied in  the  body-plan  the  same  as 
though  they  were  cants  ;  in  a  word, 
they  are  cants  in  all  respects,  and  should 
so  be  laid  down  and  bevelled,  as  also 
all  the  hawse  timbers  that  are  canted. 
It  is  seldom,  however,  that  hawse  pieces 
are  laid  down  in  private  yards ;  it  is 
sufficiently  convenient  to  make  tlje 
mould  after  the  ship  is  raised  and  regu- 
lated from  the  harpens  ;  they  can  then 
be  canted  to  suit  the  timber;  in  arrang- 
ing the  hawse  pieces  and  the  knight- 
heads,  we  should  have  reference  to  the 
hawse-holes,  and  not  put  a  long  timber 
in  the  bow  to  be  cut  off.  It  is  quite  com- 
mon in  England  to  locate  the  hawse- 
hole  either  on  the  draft  or  on  the  floor  ; 
the  bevellings  of  the  heels  of  the  cant- 
ed hawse  piece  and  knight-head  is  also 
obtained  as  those  of  the  cants ;  their 
heels  end  on  the  bearding-line,  as  also 
do  the  heels  of  the  cants;  all  of  which 
may  be  obtained  from  the  sheer-plan, 
by  placing  the  stock  of  the  bevel  in  a 
vertical  line  with  the  timber  on  the 
dead-wood,  the  heel  of  the  bevel  up  ; 
let  the  tongue  of  the  bevel  turn  forward 
or  aft  in  the  direction  of  the  timber  ; 
that  is  to  say,  if  the  timber  be  on  the 
forward  side  of  the  frame,  let  the  tongue 


be  forward,  and  set  to  the  bearding- 
line  ;  these  bevels  should  also  find  a 
place  on  the  copy  as  well  as  the  bevel- 
ling-boards  for  use. 

Having  concluded  our  expositions 
on  the  knight-heads  and  hawse  pieces, 
we  shall  leave  the  bow  for  the  present, 
and  follow  the  course  marked  for  this 
chapter  on  the  stern  of  the  ship. 

Few  ships  are  built  for  commercial 
purposes  with  other  than  square  sterns, 
although  it  has  been  taken  for  granted 
that  they  do  not  furnish  an  equal 
amount  of  strength  with  those  that  are 
usually  termed  round  sterns.  It  has 
generally  been  assumed  that  a  stern 
frame  was  indispensably  connected  with 
the  square  stern  ;  for  the  present  we 
will  only  add,  that  it  does  not  follow 
that  one  is  consequent  upon  the  other. 
In  defining  the  boundary  line  of  the 
stern  frame,  we  are  not  compelled  to 
follow  the  stereotyped  dogmas  of  our 
English  cotemporaries,  who  have  found 
it  necessary  to  have  a  transom-plan  on 
a  separate  part  of  the  floor. 

The  fashion-piece  to  which  the  ends 
of  the  transoms  are  attached,  may  be 
seen  in  the  half-breadth  plan  forming  a 
single  timber  in  most  cases,  and  leav- 
ing an  opening  between  itself  and  the 
after  cant,  equal  to  that  of  those  be- 
tween the  cants  themselves.  Some 
judgment  may  be  found  necessary   in 


striking  in  the  line  showing  the  fashion- 


34 


266 


MARINE    AND    NAVAL    ARCHITECTURE 


piece,  inasmuch  as  the  length  and 
breadth  of  the  transoms  are  thus  deter- 
mined. As  the  cant  frames  continue  to 
cant  more  as  they  approach  the  stern  ; 
so  also  it  may  he  fairly  expected  that  the 
fashion-piece  should  cant  more  than 
the  cant  that  is  immediately  forward 
of  it.  We  have  said  that  the  end  of 
the  main  transom  should  he  seen  on 
the  side  of  the  ship,  or  at  least  a  por- 
tion of  the  same;  hence  it  would  seem 
to  follow  that  this  boundary  line  was 
unalterably  fixed;  we  have  also  said 
that  this  matter  should  be  attended  to 
when  regulating  the  cants  in  the  half- 
breadth  plan  ;  allowance  for  only  a  sin- 
gle timber  need  be  made,  although 
another  timber  is  sometimes  added  be- 
low ;  the  only  proper  boundary  lines  of 
the  stern  frame  are  the  margin  line  on 
the  post  and  the  joint  of  the  fashion- 
piece  in  the  fore  and  aft  direction,  and 
the  top  of  the  main  transom,  and  the 
lower  side  of  the  lower  transom.  It 
may  seem  to  be  an  erroneous  view  ta- 
ken of  the  stern  frame  to  exclude  the 
stern  post,  but  a  moment's  reflection 
will  counteract  the  influence  of  that 
opinion  ;  the  stern  post  will  have  a 
place  in  its  present  location,  even 
though  there  were  no  stern  frame. 

It  will  be  discovered,  that  however 
desirable  it  may  be  to  spring  the  ends  of 
the  cross-seam,  or  transom  forward,  in 
order  to  ease  the  quarter,  it  cannot  be 


done  without  adding  to  the  difficulty  in 
obtaining  transoms  that  will  work  to 
the  size  and  bevels  required.  The 
transoms  are  usually  placed  in  the  fol- 
lowing order  :  the  upper  or  main  tran- 
som is  usually  sided  from  12  to  16 
inches  for  ships,  one-third  of  which  is 
kept  above  the  cross-seam  for  a  lodg- 
ment for  the  heels  of  the  counter  tim- 
bers ;  the  remaining  parts  below  are 
designed  for  the  reception  of  the  wood- 
ends  of  the  plank  ;  but  inasmuch  as  a 
portion  is  kept  above  the  line  demark- 
ing  the  cross-seam,  the  remaining  two 
thirds  are  insufficient ;  hence  it  follows 
that  another  transom  has  been  added 
immediately  below  the  main  transom  ; 
the  lower  transoms  are  usually  sided 
about  10  to  12  inches,  in  proportion 
to  the  size  of  the  ship,  or  to  the  siding 
size  of  her  frame  ;  they  are  usually 
placed  from  3  to  4  inches  apart  :  this 
course  is  almost  universally  adopted 
for  durability;  they  may  generally  stand 
with  their  faces  or  top-sides  parallel  to 
the  keel,  which,  as  a  consequence,  is 
horizontal,  inasmuch  as  few  ships  are 
built  with  a  drag  line,  or  much  rake  to 
the  post  ;  hence  it  will  at  once  be  seen 
that  little  can  be  gained  by  canting  the 
transoms,  as  is  sometimes  done  in  the 
Navy,  but  for  which  no  good  reason 
can  be  assigned,  their  be  veilings  not 
being  materially  altered,  while  a  ship 
has  little  or  no  rake  to  her  stern  post. 


MARINE  AND  NAVAL  ARCHITECTURE. 


207 


One  other  remark,  and  then  we  shall 
proceed  to  showing  the  manner  of  lay- 
ing them  off. 

The  transoms  may  be  regarded  as 
so  many  breast  hooks  placed  in  the 
frame,  instead  of  placing  them  across 
the  inside  of  the  timbers.  As  the  ends 
of  the  transoms  are  bounded  by  the 
fashion-piece,  it  is  necessary  that  the 
joint  of  the  fashion-piece  should  be 
shown  in  the  sheer-plan  ;  it  is  seldom, 
however,  done  on  the  floor,  but  always 
on  the  draft ;  their  vertical  position  on 
the  draft  is  also  shown,  running  hori- 
zontal until  they  intersect  Avith  the 
joint  of  the  fashion-piece.  We  have 
already  shown  that  they  were  bounded 
on  the  aft  side  by  the  margin  line  ;  their 
intersections  with  this  line  may  be 
squared  down  to  the  side  line  of  the 
half-breadth,  and. a  perpendicular  also 
drawn  from  the  back  of  the  main  tran- 
som or  the  cross-seam  to  the  same  in 
the  half-breadth  plan.  The  section- 
lines  have  been  described  and  illustra- 
ted in  Plate  4.  It  will  be  seen  that  the 
section-lines  come  directly  across  the 
transoms;  they  may  be  adjusted  in  the 
half-breadth  plan,  so  as  to  suit  the  tran- 
soms, and  then  swept  in  the  sheer-plan 
by  taking  the  heights  above  the  base 
of  their  intersections  with  the  frames 
in  the  sheer-plan,  as  shown  on  page 
137  ;  and  were  it  necessary  to  furnish 
a  proof  for  cant  frames,(after  the  lines 


have  been  fully  proved  before  the  cants 
were  swept  in,)we  might  find  in  the 
section-lines  all  that  we  required.  It 
will  be  seen  that  those  lines  running 
across  the  transoms  and  cants,  will 
enable  us  to  obtain  spots  at  any  part 
we  may  require  the  same  ;  but  apart 
from  this,  we  already  have  the  section- 
lines  on  the  floor  agreeing  with  the 
lines  already  proved ;  hence  it  is  only 
necessary  to  take  off  the  transoms  by 
taking  the  distance  of  their  intersec- 
tion, from  the  perpendicular  in  the 
sheer-plan,  to  the  crossing  of  the  edges 
of  the  transoms,  as  shown  in  the  sheer- 
plan  ;  let  these  intersections  or  cross- 
ings be  squared  down  to  their  corres- 
ponding sections  in  the  half-breadth 
plan ;  let  also  the  ends,  as  shown  in 
the  sheer-plan,  be  squared  down  to 
their  intersection  with  the  joint  of  the 
fashion-piece  in  the  halt-breadth  plan  ; 
battens  may  now  be  applied  to  these 
spots,  and  lines  swept  in,  which  will 
show  the  ending  as  well  as  the  shape 
of  the  transoms.  It  will  be  observed 
that  the  same  remark  will  apply 
to  the  bevelling  edges  that  we  have 
made  in  reference  to  the  upper  or 
moulding  side,  as  transoms  should,  as 
a  general  rule,  be  counter-moulded. 
The  transoms  may  now  be  laid  out 
in  the  body-plan,  simply  by  striking 
lines  across  the  after-body  side  of  the 
plan,  at  the  heights  as  taken  from   the 


26S 


MARINE    AND    NAVAL    ARCHITECTURE 


sheer-plan.  The  length  may  then  be 
taken  square  from  the  middle-line  of 
the  half-breadth  plan  to  the  intersec- 
tion of  the  moulding-edges  of  the  tran- 
soms with  the  fashion-piece  ;  or  in 
other  words,  take  the  shortest  distance 
from  the  middle-line  to  the  intersection 
of  the  moulding-edge  of  all  the  tran- 
soms, with  the  line  showing  the  mould- 
ing-edge of  the  fashion-piece  in  the 
half-breadth;  transfer  these  lengths  so 
taken  to  the  body-plan  on  the  same 
transoms  on  which  they  were  taken  ;  a 
line  cutting  those  lengths  will  show  the 
actual  lengths  of  the  transoms,  and  the 
square  fashion-piece,  or  the  fore  and 
aft  view  of  the  fashion-piece  when  in 
its  place  ;  the  lengths  or  the  settings-off 
for  the  fashion-piece,  as  shown  by  the 
mould,  is  obtained  by  measuring  in  the 
direction  of  the  line  showing  its  siding 
face  in  the  half- breadth  plan  ;  that  is 
to  say,  lay  the  batten  along  the  line 
showing  the  cant  of  the  fashion-piece, 
the  end  from  which  we  measure  being 
placed  at  the  middle-line  •,  then  mark 
the  moulding-edges  at  the  point  where 
they  strike  the  fashion-piece;  take  these 
settings-off  and  set  off  as  before  in  the 
body-plan.  It  will  be  observed  that 
the  last  settings-off  extend  beyond  the 
former,  and  both  represent  the  same 
timber,  and  are  taken  from  the  same 
plan  ;  the  difference  lies  just  here  :  the 
former  is  what  is  very  properly  termed 


the  square  fashion-piece,  and  the  latter 
the  canted  fashion-piece  ;  the  former 
line  determines  the  length  of  the  tran- 
soms, the  latter  the  length  and  shape 
of  the  fashion-piece  ;  and  yet  both  come 
together  when  in  their  place  ;  this 
operation  is  designed  for  the  purpose 
of  proving  the  accuracy  of  the  work  ; 
if  there  is  no  error,  they  will  agree; 
Plate  16  is  designed  to  illustrate  the 
stern  frame,  and  the  manner  of  opera- 
tion forlayingthem  down  and  construct- 
ing the  same.  It  is  sometimes  the  case 
that  a  second  fashion-piece  is  required, 
to  enable  us  to  fdl  out  to  the  main  or 
first  one ;  this  is  generally  short,  ex- 
tending across  three  or  four  of  the  low- 
er transoms,  and  as  low  as  the  side  line  ; 
when  this  is  required,  we  have  only  to 
set  off  its  size  aft  of  the  main  fashion- 
piece  in  the  half-breadth  plan,  as  high 
as  it  is  designed  to  go  ;  it  should  cut  off 
on  the  middle  of  one  of  the  transoms; 
it  maybe  squared  up  to  the  sheer-plan, 
and  from  thence  taken  to  the  body- 
plan,  or  may  be  taken  direct  from  the 
half-breadth  plan — the  results  are  the 
same  in  both  cases. 

From  the  nature  of  horizontal  tran- 
soms, it  will  appear  evident  that  they 
may  be  readily  shown  in  the  three  plans, 
two  of  which  show  their  edges  and  fore 
and  aft  width  only  ;  this  arrangement 
is  doubtless  readily  understood  by  the 
reader.      The  subject  of  stern  frames  is 


MARINE    AND    NAVAL    ARCHITECTURE, 


269 


not  as  complicated  as  it  would  seem  to 
be.  English  architects  have  thrown 
around  this  part  of  the  ship  a  labyrinth 
of  mystery  that  has  served  to  discour- 
age many  from  daring  to  grapple  with 
this  seemingly  complex  part.  The 
manner  in  which  the  subject  has  been 
treated  is  in  itself  enough  to  discourage 
the  beginner  ;  they  have  assumed,  and 
even  averred,  that  it  is  necessary  to 
make  a  transom  plan,  and  then  canting 
the  transoms  with  the  sheer,  or  one  at 
least  ;  and  again  canting  the  transoms 
from  a  square  with  the  margin  line 
tends  to  confuse.  Now  we  say  that  it 
is  not  necessary  to  show  them  on  the 
floor  on  more  than  one  plan,  that  is  the 
half-breadth.  We  have  described  them 
in  the  sheer  and  body-plan ;  it  is  only, 
however,  for  the  draft,  nor  yet  is  it  ne- 
cessary to  sweep  in  the  square  fashion- 
piece  on  the  floor. 

We  have  shown  that  the  line  form- 
ing the  moulding-edge  of  the  transoms 
extended  from  the  margin-line,  or  in- 
side of  the  post,  to  the  line  showing  the 
face  or  mouldino-edge  of  the  fashion- 
piece.  It  must  be  quite  clear  that 
although  the  line  may  be  continued  to 
the  margin-line,  the  transoms  cannot 
extend  to  the  same  line,  for  this  rea- 
son :  were  there  no  other,  there  would 
be  a  cavity  between  the  transoms  aft 
against  the  stern-post ;  thus  it  will  at 
once  be  seen  that  there  would  be   no 


place  for  fastening  the  wood-ends,  unless 
they  should  chance  to  come  on  a  tran- 
som ;  we  may  set  off  in  the  sheer-plan 
a  distance  equal  to  what  the  builder 
may  think  necessary,  both  at  the  cross- 
seam  and  at  the  lower  transom,  re- 
membering that  as  the  size  fore  and 
aft  is  increased,  the  breadth  is  also  in- 
creased, if  it  is  designed  to  fill  out  to 
the  moulding-edge  of  the  transoms. 
The  shape  of  the  ship  has  some  con- 
nection with  the  size,  both  fore  and 
aft,  and  thwartships  ;  if  the  vessel  be 
full  close  aft,  this  inner  post  must  not 
be  as  large  ;  if  lean  or  quite  thin  aft, 
the  size  should  be  increased.  The  in- 
ner post,  however,  may  and  should  ex- 
tend several  inches  forward  of  where 
it  would  fail  to  continue  the  shape  of 
the  transoms  ;  this  is  for  the  purpose 
of  boxing  the  transoms  into  or  over 
the  inner  post,  or  we  may  do  both  ; 
that  is  to  say,  cut  part  out  of  each. 

We  may  sum  our  remarks  up  into 
this,  that  we  may  be  better  understood  : 
first  determine  the  siding  size  of  the 
inner  post ;  set  off  half  its  siding  size 
in  the  half-breadth  from  the  middle-line; 
the  line  will  of  course  be  a  section-line  ; 
square  up  the  crossings  at  the  several 
transoms  to  their  stations  in  the  sheer- 
plan  ;  apply  a  batten  to  these  spots, 
and  we  have  the  fore  and  aft  size  of 
the  inner  post,  without  the  letting  down 
allowance  ;   we  not  only  have  the  size, 


270 


MARINE    AND    NAVAL    ARCHITECTURE. 


but  the  mould,  or  the  line  to   make  it 
by  ;  strike  a  line   as  much  forward  of 
this  line  as  we  would  let  the  transoms 
down,    and   we  require  no  more ;   the 
mould    for  the   inner  post   should   ex- 
tend its  whole  length,  which  is  from  the 
top  of  the  keel  to  the  lower  side  of  the 
second  transom,  numbering  the  main 
transom,    inasmuch   as    this    transom, 
and  the   one  below  it,  come  together, 
they    should    seat    on    the    post    itself 
when  it  is  placed  more  inside,  and  less 
outside  of  the  ship,  for  reasons  shown 
on   page  103.     When  this  method   is 
adopted,  we  require  the  siding  size  of 
the  post  to  be  larger,  as  already  shown, 
and  we  may  show  half  of  its  siding  size 
in  the  half-breadth,  as  described  in  de- 
lineating the  inner  post.     If  the  stern 
and  inner  post  have  a  taper,  oris  sided 
more  at  the  head  than  at  the  heel,  as 
in  all  cases  it  should  be,  we  may  square 
down  the  heel  or  the  intersection  of  the 
margin-line    with  the    base-line ;  take 
half  the  size  of  the  post  at  that  point, 
and  set  it  off'  in  the  half-breadth  from 
the  middle-line  ;  likewise  at  the  head 
in  the  same  manner  at  the  cross-seam 
set  off  half  the  size  of  the  post  ;   strike 
a  line  from  one  to  the  other.      It  will 
be  discovered  that  the  crossing  of  this 
line    and    the    moulding-edges   of  the 
transoms,  if  squared  up  to  the   sheer- 
plan,  will  give  spots  by  which  to  sweep 
in  the  seating   of   the  transoms  ;     an 


allowance  may  be  made  for  boxing  if 
required.  It  would  not  be  expected 
that  the  post  should  till  the  whole  cavi- 
ty, if  extending  any  considerable  dis- 
tance forward  ;  it  will  be  observed, 
however,  that  a  piece  might  fill  up  the 
cavity  shown, as  it  is  sometimes  the  ease, 
that  the  transoms  do  not  furnish  the 
surplus  that  the  inner  post  lacks. 

Having  shown  the  maimer  of  at- 
ranging  the  transoms,  and  of  obtaining 
their  form  or  shape  in  the  several  plans, 
we  may  now  show  the  manner  of  taking 
the  bevels  of  the  same.  'The  section- 
line,  it  will  be  observed,  runs  in  a  par- 
allel direction  with  the  middle-line  of 
the  ship,  and  it  must  follow  that  the 
bevel  must  be  taken  and  applied  in  this 
direction,  if  taken  or  applied  by  sec- 
tion-lines ;  hence  it  must  be  quite  ap- 
parent that  it  is  a  somewhat  difficult 
matter  to  apply  the  bevel  correctly  ; 
for  these  reasons  we  would  not  attempt 
to  take  the  bevel  of  the  transoms  from 
the  sheer-plan,  even  though  the  sec- 
tion-lines from  which  they  are  formed 
run  in  directly  a  square  line  from  their 
face ;  it  is,  however,  only  square  one 
way,  and  to  take  and  apply  bevels  cor- 
rectly, we  should  take  them  and  apply 
them  square  all  ways,  or  very  nearly  so: 
but  this  discrepancy  is  not  confined  to 
the  section-line;  in  the  water  and  diago- 
nal lines  will  be  found  the  same  diffi- 
culty, if  it    may  be  so    denominated  ; 


MARINE   AND    NAVAL    ARCHITECTURE. 


271 


hence  we  say,  instead  of  bevelling  the 
transoms,  counter  mould  them,  or 
mould  them  on  the  lower  side  ;  the 
shape  for  the  mould  of  the  lower  side 
is  obtained  in  the  same  manner  as  that 
of  the  upper.  The  ends  of  all  horizontal 
transoms  is  square  :  we  mean  by  this 
that  the  ends  coming  against  the  fash- 
ion-piece have  no  bevel,  but  are  cut 
square  from  the  top-side  up  and  down, 
and  by  the  end  of  the  mould  thwart- 
ship;  the  bevels  of  the  seats  of  the 
transoms  are  .taken  from  the  inner  post, 
as  shown  in  the  sheer-plan  ;  the  stock 
of-  the  bevel  being  horizontal,  and  the 
tongue  extending  down  along  the  line 
of  inner  post,  gives  the  bevel,  as  we 
have  before  remarked. 

We  cannot  attempt  to  define  the 
size  of  the  inner  post,  or  of  other  parts 
of  the  stern  frame,  the  judgment  of 
the  builder  must  do  this.  We  believe 
that  this  is  all  that  should  be  done; 
the  man  who  has  not  confidence  to  fill 
up  the  sizes  proportionate  to  the  size 
of  the  vessel,  is  not  qualified  to  build 
a  ship,  let  him  know  how  ever  so  well. 

The  bevels  of  the  main  transom  may 
be  taken  from  the  section-lines,  or  a 
mould  may  be  made  for  the  lower  side; 
the  mould  is  preferable.  The  mould- 
ing-edge of  the  lower  side  of  the  main 
transom  is  the  same  for  the  top-side  of 
the  one  below,  so  that  nothing  is  lost 
by    the  mould.      The    starting  line,  or 


as  it  is  sometimes  called,  the  margin- 
line,  from  which  the  bevels  commence 
on  the  back  of  the  main  transom,  and 
which  we  have  denominated  the  cross- 
seam,  is  generally  square  from  the  mid- 
dle-line when  its  form  is  not  otherwise 
defined  by  the  model ;  there  should  be 
a  sheer-line  terminating  here  on  models 
generally  ;  the  back  of  the  transom 
is  left  square  above  the  cross-seam  ; 
the  end  of  +he  main  transom  being 
shown  on  the  side,  cuts  oft' by  the  first 
breadth..  If  that  breadth  terminates  at 
the  cross-seam,  and  whether  it  does  or 
not,  it  is  no  difficult  matter  to  show 
the  height  of  the  top  of  the  transom  in 
the  body-plan,  by  a  line  extending 
across  several  of  the  cant  frames  ;  let 
these  be  taken  off*  square  from  the  mid- 
dle-line to  their  crossing  the  line  just 
run  in  for  the  top  of  the  transom  ;  these 
settings-off  must  now  be  applied  as  the 
same  frames  in  the  half-breadth  plan, 
and  a  batten  applied  to  the  spots,  which 
will  show  the  length  of  the  main  tran- 
som ;  a  mould  should  be  made  by  this 
line,  and  if  the  back  of  the  transom  has 
a  curve,  the  mould  will  show  it,  but 
the  principal  object  in  having  a  mould 
for  the  main  transom,  is  to  give  the 
exact  length  and  bevel  of  the  end,  fore 
and  aft  ;  the  mould  need  extend  no 
farther  than  the  centre  or  middle-line. 
We  have  shown  the  manner  of  lay- 
ing down   the  stern   frame,   assuming 


272 


MARINE    AND    NAVAL    ARCHITECTURE. 


the  ship  to  have  a  square  stern,  but  it 
does  not  follow  that  this  must  necessa- 
rily be  the  case.  Ships  have  been  built 
with  round  sterns,  and  yet  with  a  stern 
frame,  but  the  instances  are  rare  in- 
deed, and  we  do  not  believe  that  any 
private  builder  would  be  thus  reckless 
of  the  cost  of  this  part  of  the  ship. 

There  are  many  who  suppose   that 
the  stern  frame  is  as  indispensable  to 
the  ship  as  the  masts.     We,  however, 
are  not  of  the  number ;   we  not  only 
believe  that  the  transomed  stern  frame 
can  be  dispensed  with  in  round-stern 
ships,  but  in  square  sterns  also ;    and 
we  have  yet  to    learn   that    the    ship 
with  a  square-stern   is  not    better  in 
every  respect  without   a   stern  frame 
than  with  one,  public  opinion  to  the 
contrary  notwithstanding.      That   the 
stern  frame  is  strong,  cannot  be  ques- 
tioned, but  the  difficulty  lies  higher,  at 
the  connection  of  the  stern  above  with 
the  stern   frame   below.      In   our   ex- 
positions of  the  stern  frame,  we  showed 
a  margin  of  several  inches  above  the 
cross-seam  ;  the  object  of  this  margin 
is    to  connect  the  stern   to   the  stern 
frame,  by  boxing  in  the  counter  timbers. 
We  have  shown  this  kind  of  stern 
to  be  the  weakest  part  of  this  end  of 
the  ship,  in  consequence  of  the  man- 
ner of  connecting  them,  and  the  end- 
ing of  all  the  bottom  plank  at  this  con- 
nection. 


No    one  would   be   lost    in    wonder 
were    we    to  approve    of  canting    the 
frames  all  around  the  stern  of  a  round 
stern  ship.     It  would  be  regarded  as  a 
kind  of  matter  of  course  ;   it  is  a  com- 
mon practice ;    but  to  cant  the  square 
stern   ship    all    around,    would    be    re- 
garded  as  the  scheme  of  some  addle- 
pated  theorist.      We  are  not  surprised 
when  we  hear  men  talk  thus,  knowing 
full  well  that  it   is  an  easy  matter  to 
persuade  ourselves  to  the  belief  of  what 
we  want  to  be  true,  even  though   the 
dictates  of  common  sense  pronounce  it 
wrong.    We  would  not  be  understood  to 
say,  that   we  are  lending  a  preference 
to  square  sterns  to  our  ships  ;  we  are 
selecting  for  no  one  ;   we  are  only  en- 
deavoring to  show  what  may  be  done, 
viz.,  a  square   stern  without    a    stern 
frame,    and     with     the    cant     frames 
extending  aft   of  the   quarter  to   the 
centre  of  the  stern.     It  may  have  been 
thought    that    this    arrangement    was 
more   costly,  and,   consequently,  to  be 
repudiated  on  this  account ;   but  this  is 
not  the  case.     When  it  is  determined 
to  arrange  the  cants  around  the  entire 
stern,  we  should  have  reference  in  the 
half-breadth  to  the  corner  or  the  part 
at  which  the    fashion-piece  is  usually 
located,  as  shown  by  Plate  17.      The 
joint  of  the  cant  that  shows  the  corner 
should  intersect   with  the   end  of   the 
top  height  line ;  this  would  bring  one 


MARINE    AND    NAVAL    ARCHITECTURE, 


273 


timber  of  the  frame  on  the  stern,  and 
the  other  on  the  side  of  the  ship;  this 
arrangement,  it  will  be  understood, 
must  be  made  in  the  half-breadth  plan. 
Aft  of  this  frame,  on  a  small  ship  of 
500  to  700  tons,  one  frame  is  enough, 
iu  addition  to  the  centre  counter  timbers. 
If  a  short  timber  is  required  above  the 
cross-seam,  it  may  be  put  in  after  the 
ship  is  raised  ;  but  in  no  case  will  more 
than  two  frames  be  required  on  the 
stern,  if  properly  arranged,  as  will  ap- 
pear manifest  upon  reflection,  that 
those  frames  with  chocks  between  the 
timbers  cover  considerable  surface, 
and  at,  as  well  as  below  the  cross-seam, 
we  have  all  the  timber  we  could  desire 
for  the  durability  of  the  ship  ;  and  it 
should  not  be  forgotten  that  we  only 
require  enough  above  the  cross-seam 
to  hold  the  stern  plank  sufficiently  se- 
cure ;  all  beyond  this,  does  more  harm 
than  good.  By  adding-  extra  weight, 
we  do  not  add  strength  to  the  ship  ; 
and  in  all  cases  where  there  is  a  half 
top-timber  required  on  the  frames  of 
the  stemi,  they  should  be  of  cedar,  on 
account  of  their  being-  light.  After 
the  cants  are  arranged  in  the  half- 
breadth  plan,  we  may  lay  off  our  sec- 
tion-lines also  in  the  half-breadth  plan  ; 
it  is  assumed,  however,  that  before  this 
arrangement  is  made,  the  ship  has  been 
carried  through  a  sufficiency  of  proofs 
on  the   floor,  to  furnish  data  from  the 


lines  from  which  we  may  obtain  the 
cross-seam,  on  the  lines  shown  in  the 
half-breadth  plan,  and  on  those  shown 
in  the  sheer-plan.  The  first  opera- 
tion then,  is  to  define  the  boundary 
line  of  the  stern,  which  is  the  cross- 
seam.  We  do  this  in  the  following  man- 
ner :  as  we  already  partially  described 
in  connection  with  our  remarks  on 
Plate  4,  on  the  manner  of  running  in 
section-lines,  for  which  see  page  137, 
and  onward  ;  by  thuS  squaring  up  the 
spots  where  the  section-lines  cross  the 
cants  in  the  half-breadth  to  the  section- 
lines  in  the  sheer-plan,  we  have  spots 
for  the  thwartship  view  of  the  cants  in 
the  sheer-plan  ;  but  if  the  section-lines 
have  not  been  run  in  the  sheer-plan, 
we  should  run  them  in  at  once,  as  their 
endings  determine  the  cross-seam  in 
the  following  manner :  assuming  the 
cross-seam  to  be  square  on  the  aft  side 
with  the  middle-line,  it  then  follows 
that  all  the  section-lines  that  come  on 
this  square  part,  or  as  far  as  it  runs 
square,  will  end  in  one  place,  fore  and 
aft-wise ;  but  then  again,  it  does  not 
follow  that  they  will  end  at  the  same 
height  ;  they  may  rise  successively 
above  each  other,  and  will  so  rise  on  a 
well-formed  stern.  We  determine,  in 
the  first  place,  the  rake  of  the  stern  in 
the  sheer-plan,  both  at  the  centre  and 
at  the  corner;  hence  it  follows,  that  as 
our  sheer-lines  end  on  the  corner,  their 


35 


274 


MARINE    AND    NAVAL    ARCHITECTURE. 


ending  may  be  squared  down  to  the 
half-breadth  on  the  corner  and  on  the 
centre  of  the  stern  each  to  their  respec- 
tive places  in  the  half-breadth  plan  ; 
and  having  the  shape  of  the  stern  form- 
ed in  the  half-breadth,  we  have  the 
means  of  regulating  the  corner  in  the 
sheer-plan,  by  adding  another  sheer- 
line  or  section-line  running  only  a  short 
distance.  It  is  of  more  importance  to 
define  the  corner  of  the  stern  when 
the  cants  extend  all  around  than  when 
the  ship  has  a  stern  frame,  because 
when  the  stern  frame  finds  a  place  in 
the  ship,  the  corner  is  determined  after 
the  ship  is  raised  ;  this,  we  are  per- 
suaded, is  a  universal  practice  in  this 
country  ;  in  building  square  stern 
merchant  ships,  it  is  true,  the  fashion- 
piece  sometimes  runs  up  to  the  rail, 
but  this  does  not  show  the  corner. 
We  have  often  wondered  why  our 
builders  did  not  lay  down  and  take  the 
bevels  of  the  corner  counter-timber,  in- 
asmuch as  they  possessed  the  same  fa- 
cilities for  determining  its  form  and 
bevels  that  they  did  of  any  other  timber 
in  the  ship,  and  no  one  will  question 
the  superior  advantages  of  this  method 
over  the  present  mode  of  making  the 
moulds  after  the  ship  is  raised.  We 
think  the  manner  of  obtaining  the  form 
of  the  corner  of  the  stern  in  the  dif- 
ferent positions — that  is  to  say,  the  side 
view  at  its  proper  rake  from  the  sheer- 


plan,  and  the  perpendicular  view  at  its 
proper  rake  from  the  half-breadth  plan, 
has  been  made  plain  ;  and  it  now  only 
remains  for  us  to  furnish  the  man- 
ner of  obtaining  the  half-breadths 
and  perpendicular  heights  of  the  stern, 
when  seen  horizontally  in  the  body- 
plan  ;  this  is  accomplished  by  taking 
the  heights  from  the  sheer  on  the  sev- 
eral section-lines,  (which  should  also  be 
shown  in  the  body-plan,)  and  the  half- 
breadths  from  the  half-breadth  plan. 
Having  the  cross-seam  line,  shown  in 
the  body-plan,  we  may  be  able  to  regu- 
late the  line  showing  the  corner  or 
boundary  line  of  the  stern,  both  in  the 
sheer  and  half-breadth  plans,  to  our 
entire  satisfaction,  inasmuch  as  the 
ending  of  all  the  lines  terminate  here 
or  partially  so  ;  at  any  rate,  there  is  a 
brake  in  every  line  here,  or  as  is  a 
common  expression  in  the  ship-yard, 
there  is  an  anchor  stock  in  the  lines  here 
at  this  boundary  line. 

It  must  appear  manifest  that  if  the 
whole  quarter  were  carried  out  fair 
with  the  side  and  bottom,  it  only  re- 
mains to  fix  the  mark  around  the  quar- 
ter and  buttock  for  cutting  oft'  the 
stern,  and  to  obtain  this  is  to  obtain 
the  cross-seam  line  on  the  boundary 
line  of  the  stern  (on  the  inside  of  the 
plank,)  or  of  the  timbers  before  the 
plank  is  put  on ;  hence  we  have  shown 
that  the  length  of  the  lines  is  measur- 


MARINE    AND    NAVAL    ARCHITECTURE. 


275 


ed  from  their  ending,  and  their  endings 
is  shown  in  the  following  order:  first, 
we  have  the  heights  and  lengths  in  the 
sheer-plan,  the  lengths  and  half-breadths 
on  the  rake  of  the  stern  from  the  half- 
breadth  plan,  and  the  horizontal  and 
vertical  boundary  line  defined  in  the 
body-plan  ;  thus  provided,  we  are  fully 
prepared  to  carry  out  the  illustrations 
in  relation  to  the  construction  of  sec- 
tion-lines from  the  cross-seam  to  the 
rail,  as  shown  in  Plate  4 ;  and  this 
may  all  be  accomplished  on  the  floor 
of  the  loft,  even  before  we  make  the 
division  for  the  cants,  as  we  have  al- 
ready shown  in  our  expositions  on  the 
floor  of  the  mould  loft.  It  must  be 
quite  clear  that  if  the  longitudinal  lines 
are  all  fair,  and  are  proved  in  their  re- 
lative fullness  or  leanness  toward  each 
other,  that  nothing  remains  to  be  done 
but  to  lay  out  lines  across  the  ship,  or 
angularly,  and  they  must  of  necessity 
make  fair  frames;  hence  it  is  also  quite 
apparent,  that  this  is  not  a  proving  pro- 
cess ;  this  being  already  done,  it  is  mere- 
ly determining  the  form  shown  when  in 
a  particular  position  of  certain  sections. 
The  principal  difficulty,  if  it  may  be  so 
termed,  after  having  determined  the 
cross-seam,  is  in  the  cant  frames  cross- 
ing each  other  when  shown  on  the 
floor ;  this  is  unusual  in  the  ordinary 
cant  frames,  and  would  have  a  tenden- 
cy to  confuse  the  man  who  had  never 


seen  them  thus  spread  out  before  ;  but 
it  requires  but  a  moment's  reflection  to 
discover  that  the  cant  frames  extend- 
ing from  a  position  farther  forward  than 
they  usually  are  placed  on  the  dead- 
wood,  and  in  its  continuation  to  the 
extreme  corner  of  the  stern,  must  over- 
reach another  cant  frame  farther  for- 
ward that  cants  much  less.  In  short, 
the  shape  of  the  cants  on  the  ship  hav- 
ing no  stern  frame,  are  obtained  in  pre- 
cisely the  same  manner,  below  and  for- 
ward of  the  cross-seam,  as  those  of  the 
ship  having  a  stern  frame.  It  is  true, 
they  are  divided  or  spaced  differently, 
but  this  does  not  affect  the  manner  of 
doing  the  work  on  the  floor  after  thus 
divided  or  spaced.  Ir*the  case  of  the 
stern  frame,  the  fashion-piece  is  the 
boundary  line  ;  in  the  case  of  the  stern 
without  transoms,  the  cross-seam  is 
the  boundary  line.  We  make  this  dis- 
tinction to  relieve  the  mind  from  the 
confusion  consequent  upon  the  con- 
nection with  the  stern.  When  the  sub- 
ject is  once  fixed  on  the  mind  in  its 
simplicity,  it  is  not  difficult  to  connect 
the  part  above  the  cross-seam  with  the 
operation.  We  have  only  to  add,  that  if 
the  cants  are  taken  off  by  diagonals,  as 
in  our  former  expositions,  let  them  be 
taken  off  square  first,  and  carried  to 
the  body-plan,  to  obtain  the  proper 
height  of  the  sirmark,  as  already  ex- 
plained in  this  chapter ;   we  then  take 


276 


MARINE    AND    NAVAL    ARCHITECTURE 


the  settings-off  on  the  cant,  as  also 
shown.  This  operation  will  furnish  us 
with  the  form  of  the  cants  as  far  as  the 
cross-seam  and  no  farther,  because  the 
diagonals  themselves  run  no  higher 
than  the  cross-seam  ;  the  same  opera- 
tion is  performed  in  obtaining  the  bevels 
that  would  be, were  there  a  stern  frame; 
both  of  the  bevelling  edges  of  the  tim- 
ber on  both  sides  of  the  frame  are  shown 
in  the  half-breadth,  and  the  frame  again 
taken  off,  first  square,  to  obtain  the 
height  of  the  sirmark,  and  then  on  the 
cant,  and  applied  on  that  sirmark ;  or 
Ave  may  obtain  the  bevels  as  explained, 
by  setting  off  only  a  distance  equal  to 
what  would  allow  the  reversing  the 
bevel,  as  also  fully  explained  in  this 
chapter,  and  illustrated  in  Plate  16. 

We  cannot  entertain  a  doubt  but 
that  our  expositions  are  fully  under- 
stood. We  will  now  follow  the  subject 
in  its  continuance  from  the  cross-seam 
to  the  rail ;  this  we  shall  at  once  dis- 
cover cannot  be  performed  by  diago- 
nals, nor  yet  by  water-lines,  and  only 
by  longitudinal  or  vertical  sections ; 
the  reason  will  appear  obvious,  if  we 
will  but  reflect  that  the  diagonal  ends 
at  the  cross-seam  ;  the  water-lines  are 
found  only  below  the  cross-seam,  and 
heretofore  the  section-lines  have  ended 
at  the  cross-seam,  in  Europe  and  in 
this  country  ;  but  we  have  extended 
them  to  the  rail,  in  the  full  assurance 


that  they  may  be  rendered  of  much 
service  in  determining  mooted  points, 
or  seemingly  difficult  problems  about 
the  stern  of  ships ;  hence  it  is  plain 
from  what  has  been  shown,  that  we 
can  only  rely  upon  the  vertical  or  lon- 
gitudinal section-line  for  the  settings- 
off  necessary  to  continue  the  cant 
frames  from  the  cross-seam  to  the  rail. 
The  sheer-lines  we  have  shown  in  con- 
nection with  the  illustration  of  Plate 
4,  may  be  continued  across  the  stern,  or 
may  be  run  in  as  level  lines  from  the 
corner  to  the  centre  of  the  stern,  and  if 
there  should  not  be  a  sufficient  num- 
ber of  sheer-lines  to  accomplish  our 
purpose,  we  may  run  as  many  lines 
across  the  stern,  as  we  please,  either 
horizontal  or  raised  in  the"  centre,  as 
the  arch-board  or  taffrail,  but  this  is  or 
may  be  thought  to  be  more  difficult 
than  the  level  line,  and  the  level  line 
being  all  that  is  requisite,  we  would  re- 
commend them  when  more  is  required  ; 
these  lines  across  the  stern  are  shown 
in  the  sheer-plan,  the  half-breadth  plan, 
and  the  body-plan  ;  if  they  are  levelled 
across,  they  will  be  seen  to  be  at  right 
angles  with  the  section-lines,  both  in 
the  sheer  and  body-plan,  but  not  in  the 
half-breadth. 

The  reader  will  observe  that  we  now 
commence  in  the  body-plan,  by  taking 
the  height  from  the  load-line  (lest  we 
should  make  a  mistake  if  we  took  tin; 


MARINE    AND    NAVAL   ARCHITECTURE. 


277 


height  from  the  cross-seam)  to  this 
level  line  across  the  stern  on  any  one 
of  the  section-lines,  and  apply  the  height 
so  taken  to  the  sheer-plan  ;  we  then 
mark  it  horizontal  or  parallel  to  load- 
line  from  the  corner  to  the  centre  of 
the  stern,  which,  as  will  be  seen,  is  a 
short  distance  ;  we  next  take  the  short- 
est distance  from  a  perpendicular  line 
raised  temporarily  at  cross-seam  to  this 
line  on  the  centre,  and  on  the  corner 
of  the  stern,  and  square  those  points 
down  both  to  the  centre  and  corner  in 
the  half-breadth  plan  ;  from  these  two 
points  we  must  extend  a  curved  line 
across  the  stern,  exhibiting  the  amount 
of  round  the  stern  would  have  on  a 
level  line — that  is  to  say,  without  the 
additional  found  given  by  the  rise  of 
the  arch-board  or  taffrail,  it  will  now 
be  seen  that  the  section-lines  cross- 
ing this  curved  line  furnish  different 
lengths  from  the  cross-seam — that  is 
to  say,  at  the  centre  or  first  section- 
line,  we  shall  find  the  line  just  run  across 
the  stern  to  be  farther  aft  than  at  the 
crossing  of  the  outer  or  fourth  section- 
Jine.  This  will  furnish  us  with  data  for 
the  continuation  of  the  section-lines  in 
the  sheer-plan,  by  thus  squaring  up 
these  crossings  from  the  half-breadth 
to  the  sheer-line  continued  across  the 
stern  of  the  sheer-plan.  Having  these 
spots  furnished,  we  may  proceed  in  the 
same   manner  with  the  rail,  obtaining 


the  spots  in  the  sheer-plan  by  squaring 
up  the  intersection  of  the  sections  with 
the  rail  in  the  half-breadth  plan  ;  we 
are  thus  furnished  with  three  spots  for 
the  continuation  of  the  section-line 
from  the  cross-seam  to  the  rail ;  by  re- 
ferring to  Plate  4,  we  shall  discover 
how  they  will  be  shown  in  the  sheer- 
plan.  After  having  the  section-lines 
continued  from  the  cross-seam  to  the 
rail,  we  are  prepared  to  obtain  the  form 
of  that  part  of  each  cant  coming  on 
the  stern,  as  shown  in  Plate  17.  This 
may  be  done  in  the  following  manner: 
first,  we  observe  the  crossing  of  the 
cants  on  the  stern  by  the  section-lines 
in  the  half-breadth  plan,  square  the 
spots  or  crossings  up  to  its  correspond- 
ing section-line  in  the  sheer-plan  ;  we 
do  this  at  each  section-line  the  cant 
may  cross :  hence  it  is  plain,  that  we 
are  furnished  with  spots  from  the  cross- 
seam  to  the  rail.  The  casual  observer 
may  have  supposed  that  the  cant  on 
the  stern  must  of  necessity  be  straight 
on  the  stern,  running  as  it  does  from 
the  cross-seam  to  the  rail,  but  upon 
farther  reflection,  it  will  be  seen  that 
although  these  lines  extending  in  direct 
line  from  the  dead-wood  to  the  rail 
across  a  part  of  the  stern,  yet  it  can- 
not be  straight,  inasmuch  as  the  line 
drawn  parallel  with  the  middle-line  and 
the  stern,  is  only  designed  to  be  straight 
on  parallel  lines;  and  we  may  here  add 


278 


MARINE  AND    NAVAL    ARCHITECTURE. 


that  if  the  stern   be  quite  round,  and 
have  any  considerable  twist,  it  is  not 
straight  any  where  but  on  the  centre. 
We  have  given  an  exposition  of  the 
manner  of  running  in   the   moulding- 
edffes  of  the  cants  that  in  their  continua- 
tion  across  the  stern  supplant  the  stern 
frame.     If  we  insert  chocks  in  the  cant 
frames,  it  is  only  necessary    to  show 
another  line  in  the  half-breadth  plan, 
aft  of  the  former  line  or  joint  of  the 
frame  ;   and  the  same  course   may  be 
pursued   that  we  have  just    finished ; 
the  form  of  the  centre  counter  timbers 
are  seen  in  the  sheer-plan,  and  their 
bevel  may   be   obtained   from  the  half- 
breadth  plan,  by  showing  the  siding  size, 
and  squaring  up  the  crossings   of  the 
section-lines  with  the  bevelling  edge  to 
the   sheer-plan,  and   we  have  the  dis- 
tance  the  bevelling  edge  falls  within 
the  moulding-edge,  and  this  distance  is 
the  bevel  in  its  siding  size  ;  the  bevel- 
lings  of  the  cants,  whether  the  part  on 
the  stern,  on  the  quarter,  or  the  buttock 
are  obtained,  as  we  have  shown  in  the 
present    chapter,  either  by  running  in 
the  bevelling  edges  of  the  timbers  in 
the  cant  plan,  or  by  taking  a  distance 
from    the  moulding  side  or   face  only 
commensurate  with  what  would  avail 
for  reversion  ;  that  is  to  say,  the  bevels 
may  be  obtained  by  setting  off  in  the 
hall-breadth  plan  from  the  line  show- 
ing the   face   of  the  standing  timber, 


which  is  the  forward  timber  of  the 
after-body,  and  the  after  timber  of  the 
fore-body.  Now  let  it  be  observed,  that 
the  distance  is  determined  by  the  build- 
er ;  we  cannot  determine  the  matter, 
inasmuch  as  it  is  variable,  and  depends 
upon  the  amount  of  round  the  line 
presents  to  the  cants,  and  we  have 
shown  that  the  more  round,  the  less 
space  is  required,  see  Plate  17. 

We  have  something  to  add  in  addi- 
tion to  what  has  been  said  in  relation 
to  the  comparative  strength  of  the  stern 
with  a  stern  frame  ;  the  former  requires 
both  ribbands  and  shores  to  keep  it  up, 
while  the  latter  is  sustained  with  the 
same  size  and  kind  of  shore  that  will 
hold  any  other  frame,  showing  that 
there  is  intrinsic  strength  in  the  frame 
itself,  which  the  ordinary  counter  tim- 
ber does  not  contain  in  its  connection 
with  the  transom. 

We  have  alluded  in  the  present  chap- 
ter to  the  side  or  corner  counter  tim- 
ber, and  have  endeavored  to  show  that 
the  floor  of  the  loft  was  the  proper 
place  for  delineating  its  shape  and 
bevels,  we  shall  now  make  an  effort  to- 
show  the  manner  in  which  this  may  be 
performed,  presuming  that  there  are 
many  who  do  not  know  how  to  perform 
this  operation  ;  for  the  length  and  shape 
of  the  mould,  we  have  but  to  refer  our 
readers  to  the  half-breadth  plan,  ex- 
hibiting the  stern  in  its  distended  capa- 


MARINE    AND    NAVAL    ARCHITECTURE. 


279 


city  from  this  or  by  this  plan.  The 
mould  may  be  made  as  shown  in  Plate 
3,  Section  2.  If  we  counter  mould 
the  timber,  it  will  be  necessary  to  line 
forward  of  the  corner  in  the  sheer-plan 
its  siding  size  ;  this  new  line,  as  a  con- 
sequence, must  of  necessity  cross  the 
sheer-lines  in  the  sheer-plan  ;  let  these 
crossings  be  squared  down  to  the  half- 
breadth  plan,  and  noted  or  spotted  on 
the  same  sheer-lines  that  they  crossed 
above ;  mark  in  a  line  by  these  spots, 
and  we  have  the  bevelling  edge  of  the 
corner  counter  timber  ;  the  space  be- 
tween those  two  lines,  it  will  be  ob- 
served, is  the  bevel  without  a  square, 
provided  the  after  side  stood  across  the 
ship ;  hence  it  is  plain,  that  we  have 
not  all  the  bevel  we  require,  inasmuch 
as  the  aft  side  does  not  stand  across 
the  ship  ;  and  by  the  inboard  edge  of 
the  aft  side  being  farther  aft  than  the 
outboard  edge,  the  bevel  must  of  ne- 
cessity be  more  standing,  whence  we  at 
once  discover  that  something  more 
must  be  done  ;  we  may  consummate 
the  operation  by  applying  a  square  to 
the  middle-line  at  any  of  the  sheer- 
lines,  and  determining  how  much  the 
stern  rounds  from  a  square  at  that 
point  in  one  foot  from  the  corner; 
tliis  added  to  the  bevel  obtained  for  the 
side,  gives  all  the  bevel  we  require  at 
that  spot  ;  if  the  stern  have  a  twist, 
we  may  apply  the  square  at  each  spot 


in  the  same  manner ;  it  will  also  be 
observed,  that  the  opening  on  the  side 
between  the  two  lines  showing  the 
corner  as  the  moulding,  and  the  for- 
ward line  as  the  bevelling  edge:  in  other 
words,  the  opening  taken  for  the  bevels, 
must  be  taken  square  from  the  stern, 
and  not  in  line  or  parallel  with  the 
sheer-lines,  inasmuch  as  the  bevel  must 
be  applied  square,  and  of  course  should 
be  so  taken ;  we  sometimes  have  seen 
two  moulds  made,  but  we  deem  it  un- 
necessary, inasmuch  as  the  mould  made 
for  the  corner,  can  show  both  the  rake 
of  the  stern  and  counter  ;  this  is  done 
by  cutting  the  main  or  upper  piece  of 
#ie  mould  off  at  the  knuckle  to  the 
bevel,  both  up  and  down  and  thwart- 
ship  of  the  counter  ;  we  then  make  a 
mould  to  the  counter,  and  nail  them 
together :  the  counter  mould  lapping 
over  the  upper  piece;  the  top  of  the 
transom  will  show  the  fore  and  aft  line 
by  which  to  cut  off  the  heel  by,  and 
will  also  furnish  the  bevels  in  connec- 
tion with  the  mould. 

There  are  several  ways  of  obtaining 
both  the  form  and  bevels  of  the  corner 
counter  timber,  but  we  deem  it  unne- 
cessary to  cumber  the  pages  of  this 
work  with  more  than  a  sufficiency 
upon  any  subject.  A  few  expositions 
upon  the  subject  of  building  sterns,  and 
we  shall  have  done  with  the  subject, 
believing  that  we  have  made  the  mat- 


280 


MARINE    AND    NAVAL    ARCHITECTURE. 


tcr  clear,  and  within  the  reach  of  all 
who  will  pursue  our  expositions  con- 
nectedly. 

It  has  been  the  practice  to  mould 
the  transoms  and  fashion-piece  larger 
than  the  cants,  in  order,  that  the  ceil- 
ing might  butt  against  the  fashion- 
piece ;  this  practice  in  our  judgment 
is  decidedly  wrong.  If  the  stern  frame 
is  of  such  peculiar  construction  that  it 
cannot  be  ventilated  but  in  this  way, 
by  excluding  the  ceiling,  and  by  adding 
extra  weight  to  the  stern  frame,  it  had 
better  be  abandoned.  In  addition  to 
this  it  does  not  make  a  finish,  and  it 
must  be  quite  clear  to  the  thinking 
man  that  the  ceiling  cannot  extend 
over  the  stern  frame  any  considerable 
distance,  inasmuch  as  the  transoms 
are  heavier  or  larger  in  the  throat  than 
the  scantling  size  of  the  cants  at  the 
same  altitude  ;  and  being  usually  made 
of  straight-grained  timber,  if  they  should 
be  reduced  to  this  scantling  size,  the 
strength  would  be  partially  lost.  Thus 
we  discover  that  the  stern  frame  is  no 
great  things  after  all.  It  does  not 
make  the  strong  or  finished  job. 

The  cants  around  or  across  the 
square  stern,  we  have  no  hesitation  in 
recommending  as  being  far  preferable, 
inasmuch  as  they  equalize  the  strength, 
and  render  their  immediate  locality 
more  durable  by  affording  greater  fa- 
cilities for  ventilation,  and  at  the  same 


time  admit  of  a  continuation  of  the 
ceiling  either  to  the  lower  side  of  the 
deck  beam,  or  to  meet  against  the  dead- 
wood  or  inner  post  in  its  continuation 
as  high  as  the  head  of  the  stern  post. 

The  subject  of  making  moulds  de- 
mands our  attention  in  this  chapter, 
and  although  plain  in  itself  considered, 
yet  in  its  connection  with  the  distinc- 
tive lines  necessary  for  the  delineations 
of  the  frames  or  transverse  sections  of 
the  ship  when  chocks  are  introduced, 
the  subject  seems  to  demand  more  than 
a  passing  notice. 

There  are  three  kinds  of  moulds  by 
which  a  ship's  frame  may  be  moulded, 
only  two  of  which,  however,  should 
have  any  connection  with  the  ship- 
yard ;  those  of  the  denomination  we 
would  exclude  are  very  properly  called 
skeleton  moulds,  and  are  better  adapt- 
ed to  the  live-oak  hammocks  of  the 
southern  sea-board,  although  (they 
have  been,  and  still  are,)  used  in  our 
Navy  yards  for  moulding  the  frames  of 
ships,  and  such  other  vessels  as  are 
there  built. 

If  an  exposition  is  required  of  the 
inconvenience  of  skeleton  moulds,  we 
have  but  to  refer  to  the  floor  mould  of 
private  yards,  which  is  usually  made 
upon  this  principle.  This  mould  is 
commonly  made  in  such  a  manner  that 
it  is  capable  of  containing  all  the  floors 
of  the  fore-body   on  the  one  side,  and 


MARINE   AND    NAVAL    ARCHITECTURE. 


281 


those  of  the  after-body  on  the  other. 
It  is  formed  of  battens,  and  divided 
into  two  parts,  both  of  which  are  as- 
sumed to  be  alike,  and  each  part  hav- 
ing for  its  boundary  line  the  middle- 
line  as  a  vertical  boundary  ;  the  base 
of  the  mould  is  represented  in  the 
lower  edge  of  the  batten,  which  is 
usually  just  its  own  width  below  the 
base-line  of  the  body-plan ;  in  other 
words,  the  batten  bounding  or  showing 
the  lower  side  of  the  mould,  has  its 
upper  edge  to  the  base-line  ;  the  out- 
ward side  of  the  mould  has  a  batten 
placed  with  its  upper  edge  to  the  diago- 
nal, showing  the  floor  heads  ;  this  bat- 
ten may  extend  no  higher  than  is  re- 
quired for  the  reception  of  the  sharpest 
floor,  or  it  may  extend  to  the  middle- 
line  and  form  the  triangle  ;  the  two 
parts  are  united  by  hinges,  and  may  be 
closed  when  not  in  use  ;  the  several 
diagonal  lines  and  the  side  lines  are 
also  represented  by  battens,  across 
which  the  rising  of  the  seats  for  the 
dead-wood  are  marked.  When  the 
mould  is  opened  on  a  floor  timber,  the 
frame  to  which  the  floor  will  mould 
(being  marked  across  the  battens)  is 
transferred  to  the  timber  by  the  edges 
of  the  battens,  and  the  sirmarks  also 
marked,  when  the  mould  is  removed, 
and  the  first  futtock  mould  is  applied 
to  the  spots,  and  the  diagonals  com- 
pared, when  the  race  knife  is  applied, 


and  one  arm  of  the  floor  moulded  ;  the 
mould  is  then  reversed,  and  the  oppo- 
site arm  is  also  moulded.  Where  the 
entire  set  of  moulds  are  of  this  com- 
plexion, and  whole  moulds,  or  such  as 
furnish  the  entire  shape  are  not  used, 
the  space  between  the  spots  is  carried 
around  the  timbers  by  a  sweeping  bat- 
ten. 

It  must  be  quite  apparent  that  this 
manner  of  moulding  a  ship's  frame  is 
tedious  and  expensive,  inasmuch  as 
several  moulders  are  required,  even  for 
what  is  generally  deemed  a  small  com- 
pany of  operatives  or  workmen.  The 
kind  of  moulds  commonly  used  are  such 
as  show  the  shape,  scantling  size,  and 
length  of  the  timbers.  There  are  ex- 
ceptions in  which  the  scantling  size  is 
shown  bv  the  marks  on  the  mould,  and 
not  by  its  size  ;  in  such  cases  the  spots 
showing  the  size  are  set  off  from  the 
moulding  edge  and  swept  by  the  out- 
side of  the  mould. 

It  may  be  well  to  remark  in  relation 
to  the  floor  mould,  that  its  base  is 
sometimes  made  to  show  the  shape  of 
the  floor  timber,  or  its  rise  above  the 
base  ;  this  mode  is  preferable,  inasmuch 
as  it  lightens  the  mould,  which  is  an 
item  worthy  of  consideration  to  the 
moulder.  The  battens  across  the 
mould  are  not  confined  to  the  number 
of  the  diagonals  ;  there  may  be  others 
wherever  required  to  bring  the  spots  a 


36 


282 


MARINE    AND    NAVAL    ARCHITECTURE 


suitable  distance  apart.  It  will  be  ob- 
served, that  inasmuch  as  the  body-plan 
shows  but  one  side,  or  one  half  for 
each  body,  the  one  half  of  the  mould 
is  marked  by  lines  shown  in  the  body- 
plan,  and  the  other  half  is  marked  by 
the  first,  because  it  is  plain  that  both 
parts  could  not  be  marked  from  the 
floor  without  marking  the  same  side  of 
the  mould,  and  when  the  mould  was 
opened  to  show  both  arms  of  the  floor, 
the  marks  would  be  found  on  the  one 
half  upward,  while  on  the  opposite  side 
of  the  mould  the  marks  would  be  down- 
ward. 

It  is  assumed  that  the  lengths  of  the 
futtocks  have  been  properly  and  pre- 
viously arranged,  and  those  lengths  re- 
presented by  the  diagonals ;  as  a  con- 
sequence, the  only  necessity  for  a 
double  set  of  moulds  would  be  to  show 
the  lengths  of  the  futtocks ;  this  is 
strictly  true  when  there  are  no  chocks 
in  the  frame,  or  when  there  is  but  one 
line  on  the  floor  in  the  body-plan  for 
each  frame ;  but  when  (as  we  have 
shown  that  there  should  be)  there  are 
two  lines  showing  the  form  of  the  frame, 
one  on  each  side  of  the  chock,  it  will 
become  still  more  apparent  that  there 
should  be  two  sets  of  moulds  for  each 
frame — that  is  to  say,  the  several 
moulds  belonging  to  the  same  frame 
when  laid  on  the  floor  to  their  proper 
places,    will  show  two  thicknesses   of 


moulds  as  low  as  the  floor  heads,  and 
if  the  edge  of  one  course  of  moulds 
thus  laid  by  the  line  showing  the  shape 
of  the  frames  in  the  body-plan  be  with- 
in the  other,  and  the  floors  face  to 
dead-flat  frame,  it  will  make  no  differ- 
ence which  body  we  may  be  at  work 
in,  the  fore  or  after-body,  the  first  and 
third  futtock  and  top-timber  moulds 
will  show  their  edges  outside  of  the 
moulds  of  the  other  half  of  the  frame, 
viz.,  the  second  and  fourth  futtock,  in- 
asmuch as  the  under  bevelling  of  the 
floors,  second  and  fourth  futtocks  will 
cause  the  one  set  of  lines  to  fall  within 
the  other  set,  just  what  they  are  shown 
to  be  in  the  thickness  of  the  chocks, 
or  the  standing  beveilings  of  the  first 
futtock,  third  futtock,  and  top-timber 
would  cause  the  one  set  of  lines  to  fall 
without  the  other  set,  the  same  as  shown 
in  the  thickness  of  the  chocks.  We  have 
before  remarked,  that  one  set  of  lines 
may  and  should  be  marked  with  a  differ- 
ent color,  to  distinguish  them  from  the 
other  ;  4his  distinction  should  also  char- 
acterize the  moulds.  For  example, 
the  first  line  swept  in  on  the  floor 
being  the  floor  timber,  second  and 
fourth  futtock,  may  be  marked  with 
lead  pencil ;  hence  we  say  that  the 
floor  mould,  the  second  and  fourth  fut- 
tock moulds,  should  be  marked  at  all 
the  sirmarks  or  diaagonals  with  lead 
pencil  ;   the   number  or  letter    of  the 


MARINE   AND    NAVAL    ARCHITECTURE, 


2S3 


frame  should  also  be  with  pencil.  On 
the  other  hand,  the  first  and  third  fut- 
tocks  and  top-timbers  should  be  mark- 
ed with  red  chalk,  both  the  line  on 
the  floor  and  the  moulds ;  it  may  be 
well  to  observe,  the  one  mould  butts 
at  the  middle  of  the  other,  and  the 
timbers  ofwhe  frame  are  arranged  in 
the  same  maimer.  The  arrangement 
we  have  alluded  to  in  this  chapter,  of 
equalizing  the  strength  by  equally  dis- 
tributing the  butts,  need  not  alter  the 
present  arrangement  ;  the  butts  would 
be  taken  from  the  expansion  plan,  and 
marked  on  their  respective  frames,  and 
the  moulds  made  accordingly  ;  the  cant 
moulds  are  marked  in  the  same  man- 
ner where  chocks  are  introduced,  and 
their  ending  on  the  side  of  the  dead- 
wood  may  be  determined  by  making  a 
sirmark  on  the  mould  at  or  near  the 
heel,  a  given  distance  above  the  base- 
line, marking  the  distance  on  the 
mould,  and  then  by  squaring  up  on  the 
side  of  the  dead-wood  the  stations  of 
the  cants,  as  shown  on  the  side  line  of 


the  half-breadth.  We  may  on  these 
lines  set  up  the  height  of  these  respec- 
tive sirmarks,  and  we  have  the  starting 
point  for  laying  out  the  boxing,  or  as 
they  are  sometimes  called,  the  gaines ; 
the  heel  of  the  timber  itself  must  de- 
termine the  size  of  the  box  for  the  re- 
ception of  the  same.  From  what  we 
have  shown,  Jt  will  be  discovered  that 
the  moulds  are  the  representatives  of 
the  timbers,  both  in  length  and  shape, 
and  sometimes  in  size. 

In  some  parts  of  Europe  it  is  the 
practice  to  show  the  form  of  a  number 
of  frames  on  the  same  mould  by  in- 
scribing their  shape  ;  those  lines  are 
transferred  to  the  timber  by  boring 
holes  in  the  line  and  through  the 
mould  ;  these  are  shown  on  the  face  of 
the  timber  by  a  second  boring,  either 
with  gimlet  or  compasses,  and  then 
the  form  is  carried  around  the  timber 
by  the  mould  ;  but  such  expedients 
would  cost  more  than  they  would  come 
to  in  a  wooden  country  like  ours. 


284 


MARINE    AND    NAVAL    ARCHITECTURE 


CHAPTER     IX. 

Important  Rules  in  Practical  Operations — Directions  applicable  to  the  successive  stages  of  Advancement  in 
Building — Rules  for  Planking — Ceiling — Making  Spars,  &c. 


Ill  every  art  there  are  certain  prac- 
tices, the  principles  of  which  are  con- 
sequent upon  the  cultivation  of  opera- 
tive genius,  in  connection  with  the 
known  laws  of  geometrical  science. 
There  are  many  rules,  however,  in 
daily  practice  that  have  been  trans- 
mitted from  sire  to  son,  without  a 
knowledge  of  the  principles  upon  which 
they  are  based,  or  of  geometrical  sci- 
ence from  whence  they  emanate.  Wide- 
ly different,  however,  is  the  radiating 
scintillations  in  the  horizon  of  the  fu- 
ture, pregnant  with  the  hopeful  harbin- 
gers of  a  golden  era  yet  about  to  dawn. 
Above,  beneath,  and  around  us  we  see 
the  seeds  of  change — the  germinations 
of  a  new  life  springing  into  existence. 
Science  no  longer  secludes  herself 
amid  the  portals  of  the  cloistered  cell 
of  the  solitary  monk ;  nor  among  the 
impenetrable  labyrinths  of  Egyptian 
pyramids  ;  nor  yet  is  she  hushed  into 
silence  by  the  edicts  of  Platonic  philo- 
sophy. Having  become  a  univer- 
sal benefactor,  she  sheds  her  mellow- 
ing influences  on  no  secluded  walk  in 


life  or  academic  grove,  but  pours  the 
full  tide  of  her  magic  sun-beams  upon 
the  "Teat  thorouo-hfares  of  life — on 
every  pathway  of  humanity,  wherever 
human  hope  gives  birth  to  human 
effort.  Geometrical  science,  like  the 
tide-wave  that  circumnavigates  the 
globe  in  a  lunar  day,  is  destined  to 
sweep  over  the  ocean  of  mind  until  it 
has  found  a  resting-place  on  every  spot 
of  earth  that  has  been  sullied  by  the 
foot  of  man — its  march  is  inseparably 
connected  with  that  of  progress.  We 
are  persuaded  that  no  attentive  obser- 
ver, possessing  a  reflective  mind,  can 
carelessly  canvass  the  almost  startling 
changes  that  have  taken  place  in  mo- 
delling ships,  as  in  other  things,  within 
a  very  few  years.  The  well  nigh  om- 
nipotent prejudices  of  the  Old  World 
that  have  held  mechanics  stationary 
through  the  almost  interminable  lapse 
of  fabulous  ages,  is  working  a  new 
leaven  that  will  engender  a  spirit  so 
potent  and  so  resistless,  as  to  sweep 
away  every  vestige  of  its  ancient  land- 
marks ;    and    we    anticipate    the    day 


Isvv^ 


ii 


MARINE    AND    NAVAL    ARCHITECTURE, 


2S5 


when  customs  and  habits  shall  be 
valued,  not  for  their  antiquity,  but  for 
their  use — not  for  the  hoary  scalp  they 
wear,  but  for  their  utility. 

We  were  involuntarily  led  to  the 
foregoing  reflections  upon  witnessing 
the  tide  of  opposition  that  seemed  to 
be  setting  against  any  innovation  into 
the  well-known  form  set  down  for 
freighting  ships,  identified  and  known 
by  all  like  the  hat-block  or  the  last  upon 
which  shoes  are  made.  Happily  for 
the  commercial  world,  there  are  some 
who  dare  think  and  act  for  themselves 
in  modelling  vessels,  the  number,  how- 
ever, is  by  far  too  limited. 

Plate  19  exhibits  the  lines  of  a  ship 
designed  for  the  freighting"  trade  be- 
tween  this  port  and  Liverpool ;  this 
ship,  built  in  this  city,  and  known  and 
registered  as  the  Universe,  was  launch- 
ed in  March  of  the  present  year,  and 
while  building  was  visited  by  the  skep- 
tical and  the  curious;  and  it  would 
have  been  no  difficult  matter  for  a 
practised  eye  to  have  read  from  the 
observer's  glance,  the  shake  of  the 
■  head,  or  the  shrug  of  the  shoulders, 
that  she  was  set  down  by  both  ship- 
builders and  masters  as  a  ship  that 
would  be  partially,  if  not  wholly,  un- 
manageable ;  in  a  word,  that  fast  sail- 
ing and  good  steering,  were  entirely 
out  of  the  question.  The  ship  was 
finished  notwithstanding,  and  has  com- 


pleted her  first  voyage,  and  is  found  to 
roll  remarkably  easy,  steer  well,  and 
sail  fast,  as  some  ship-masters  have 
abundantly  proved,  who  were  sailing 
in  company.  We  have  made  the  fol- 
lowing calculations  from  her  lines, 
(after  adding  the  thickness  of  the  plank 
to  her  moulding  size,)  which  shows 
her  weight,  capacity,  stability,  &c. 
Her  hull  and  spars,  anchors,  cables, 
and  tank  of  2,000  gallons  of  water, 
weighed,  when  launched,  922  tons 
2,100  pounds.  This  amount  of  dis- 
placement is  contained  within  a 
draught  of  10  feet  lj  inches.  The 
weight  of  anchors,  cables,  water,  &cv 
deducted,  leaves  840  tons  1,330  pounds, 
for  the  weight  of  the  ship  ;  her  capacity 
between  that  draught  and  19  feet,  is 
equal  to  1,329  tons  1,640  pounds ;  her 
registered  tonnage  is  1,298.  She  was 
originally  designed  for  a  two-decked 
ship,  in  which  case  the  present  plank- 
sheer  would  have  been  her  rail.  The 
lines  were  taken  from  the  tables  after 
being  proved  on  the  floor ;  the  water- 
lines  or  parallels  to  the  base  are  fur- 
nished as  shown  on  the  model  ;  the 
sixth  water-line  being  an  approxima- 
tion to  the  proper  altitude  for  what  is 
properly  called  the  line  of  construction. 
We  may  learn  the  due  proportion  this 
line  should  bear  to  the  depth  of  the 
vessel,  by  referring  to  page  43  ;  out- 
calculations  on  the  stability  were  made 


2S6 


MARINE   AND    NAVAL    ARCHITECTURE. 


from  this  sixth  water-line,  it  being  with- 
in 6  inches  of  its  proper  height  ;  18 
feet  draught  of  water  would  have 
placed  the  load-line  in  its  most  appro- 
priate place,  if  the  original  design  had 
been  carried  out ;  and  the  sixth  water- 
line  being  17i-  feet,  we  adopted  that 
line  as  the  boundary  for  our  calcula- 
tions from  which  to  determine  the  sta- 
bility of  the  ship.  It  will  be  perceived 
by  referring  to  Plates  19  and  20,  that 
the  centre  of  effort  (the  altitude  of 
which  determines  the  stability  of  the 
ship)  is  2  feet  above  the  sixth  water- 
line,  or  the  constructed  line  of  flotation, 
and  that  the  centre  of  displacement  is 
10  inches  above  the  third  water-line. 
It  may  be  reasonably  inferred,  without 
entering  into  the  calculation  for  the 
actual  centre  of  gravity  of  the  ship, 
that  the  centre  of  effort  is  above  this 
point  ;  hence  we  say,  that  a  vessel  has 
stability  if  the  centre  of  effort  is  above 
the  load-line  of  flotation,  unless  the 
vessel  be  an  ocean  steamer,  or  a  river 
steam-boat.  This  description  of  vessels 
sllbuld  be  invariable  exceptions  to  the 
rule,  inasmuch  as  the  centre  of  gravity 
of  the  engines  and  boilers  is  often  found 
to  be  above  the  line  of  flotation  :  thus 
we  discover  that  it  requires  no  figures 
to  determine  that  the  centre  of  effort 
must  be  above  the  line  of  flotation,  else 
the  vessel  has  no  stability,  and  must  be 
ballasted  with  coal.     Not  so  with  sail- 


ing vessels ;  their  cargo  or  ballast  is 
designed  to  remain  permanent,  until 
the  termination  of  the  voyage  ;  in  ad- 
dition to  the  fact,  the  centre  of  gravity 
being  below  the  line  of  flotation,  in- 
creases the  stability  from  which  is  ob- 
tained the  required  leverage  of  the 
masts  for  propulsion.  AVe  consider 
the  altitude  of  the  centre  of  effort  in 
the  Universe  quite  low  enough  for  any 
sailing  vessel,  and,  indeed,  were  it  2 
feet  higher,  the  ship  would  be  better  for 
the  increased  altitude.  It  may  be  well 
to  observe,  that  the  ship  was  launched 
without  ballast,  with  her  smaller  masts 
on  end,  and  yet  evinced  no  signs  of  in- 
stability. This  is  owing  to  the  shape 
of  her  floor  transversely,  in  addi- 
tion to  keelsons,  of  which  she  had 
more  than  an  ordinary  share  ;  they 
operated  as  ballast,  enabling  her  to 
maintain  her  upright  position.  It 
seems  proper  to  remark  in  this  place, 
that  although  the  calculation  for  the 
centre  of  effort  contemplates  not  only 
the  principal  dimensions,  but  the  con- 
tents in  its  distribution  over  the  im- 
mersed portion  of  the  hull  and — as  a 
consequence — the  shape;  so  that  it  will 
be  at  once  perceived,  that  however 
much  we  may  desire  to  elude  the  in- 
vestigating scrutiny  of  figures,  we  are 
destined  to  be  subject  to  their  search- 
in"  «aze.  But  still  there  is  one  particu- 
lar  in  which  we  may  be  led  into  error 


MARINE    AND    NAVAL    ARCHITECTURE. 


287 


by  adhering  tenaciously  to  the  calcu- 
lation, without  reference  directly  to  the 
form  of  the  greatest  transverse  section. 
We  will  refer  our  readers  to  Plate  5, 
from  which  we  shall  discover  that  the 
centre  of  effort  is  higher  than  in  the 
Universe  ;  it  does  not,  however,  follow 
that  the  ship  would  have  more  stability: 
indeed,  she  would  have  less,  in  conse- 
quence partly  of  the  high  centre  of  dis- 
placement in  connection  with  the  round 
floor  transversely,  or  the  small  propor- 
tionate amount  of  flat  to  the  floor  from 
the  keel  outward  ;  in  other  words,  the 
long  bilge  transversely  has  a  tendency 
to  depreciate  the  stability.  The  Uni- 
verse has  a  very  stable  transverse  sec- 
tion, and  although  she  is  a  departure 
from  the  stereotyped  form  recognized 
for  freighting  ships,  yet  she  is  no  un- 
worthy specimen  of  the  improvements 
of  this  improving  age.  With  regard  to 
the  spars  of  this  ship,  she  is  lightly 
sparred;  and  it  will  be  seen,  by  referring 
to  Plate  20,  that  her  centre  of  propul- 
sion is  but  7  feet  10  inches  forward  of 
the  centre  of  buoyancy,  while  the  lat- 
ter point  is  without  doubt  farther  aft 
than  in  any  freighting  ship  in  the  Liver- 
pool trade  at  this  time — the  displace- 
ment of  the  two  bodies  being  about 
equal.  It  will  be  seen  that  she  weighs 
less  than  I  of  the  load-line  displacement, 
whether  taken  at  the  19  feet  or  the  17i 
feet  draught,  at   which   her    displace- 


ment amounts  to  1,929  tons,  and  her 
capacity  to  1,116  tons.  The  length 
between  the  perpendiculars  of  the  6th 
water-line,  or  L=175  feet  ;  the  ex- 
treme breadth,  or  B=37,S6  feet ;  these 
multiplied  together  —  6625,5  ;  the 
area  of  the  6th  water-line,  or  W= 
5537,12;  therefore  5537,12-6625,5 
=,835;  the  exponent  of  the  6th 
water-line,  or  W=,S35xLxB.  Let 
the  height  between  the  rabbet  and  6th 
water-line  be  H=to  15  feet,  multiplied 
by  LxB=99382,5;  divide  this  into  the 
whole  cubical  displacement  66998,75 
represented  in  D  ;  thus,  66998,75, 
4- 99382*5  =,674,  the  exponent  of  the 
cubical  displacement,  or  D=,674  x  L  x 
BxH.  The  centre  of  gravity  of  dis- 
placement is  6,52  feet  below  the  6th 
water-line  ;  therefore  H  =  15  feet,  and 
6,52  the  distance  of  the  centre  of  gravi- 
ty below  the  6th  water-line  ;  6,52  -4-  15 
=  ,435  xH  below  the  6th  water-line. 
Again,  the  plank,  keel,  stem,  and  post 
displace  ^  of  the  whole  cubical  displace- 
ment ;  the  weight  of  the  ship  calcula- 
ted at  I,  I  are  left  for  the  capacity  ; 
therefore  66998,75  x  fx £^39289,4 
cubic  feet  ;  and  as  35,2  cubic  feet  of 
sea  water  are  equal  to  1  ton  weight, 
39289,4-35,2  =  1116,1  tons  for  the 
capacity  of  the  ship  when  loaded  to  the 
6th  water-line,  or  to  draught  of  17  feet 
6  inches. 

It  may  not  be  out  of  place  here  to 


ass 


MARINE  AND  NAVAL  ARCHITECTURE 


furnish  some  rules  for  determining,  or 
approximating  the  additional  displace- 
ment for  the  plank  on  the  outside  of 
the  immersed  part  of  the  vessel.  It 
will  be  remembered  that  the  lines  by 
which  a  vessel  is  built  show  the  inside 
of  the  plank  ;  consequently  the  thick- 
ness of  the  plank  must  be  added  in  or- 
der to  determine  the  displacement, 
weight,  or  capacity  of  the  vessel. 
When  planked  with  oak,  an  allowance 
of— 

For  Ships,  -jL.  T'T  or  T'g  of  the  displacement  may  be  added. 

For  Brigs,  T\,  ^  or  & 

For  Schooners,  T\,  T\  or  -^  "  " 

For  Sloops,  T'5,  T'T  or  T'3 

For  Tow-Boats,  T\,  &  or  T\  "  "  " 

Smaller  Vessels,  Ty  TV  or  TV 

If  the  vessel's  frame  should  be  of 
lighter  material  than  oak,  say  chestnut, 
and  the  bottom  planked  with  pine,  the 
additional  displacement  for  the  plank 
may  be  set  down  as  follows  : 

For  Ships,  £>,  j%  or  /„ 
For  Brigs,  ¥65-,  /„  or  T65 
For  Schooners,  -^g,  y6s  or  y6a 


_6_ 
6  5 


_b_ 
55 


For  Sloops,  765,  T60  or  ^ 

For  Tow-Boats,  ^,  ^  or 

For  Smaller  Vessels,  ^60,  363  or  /ff. 

It  will  be  seen  that  the  tables  is  va- 
riable ;  this  is  consequent  upon  the 
thickness  of  the  plank,  and  the  distance 
down  below  the  wales  ;  the  diminish- 
ing strakes  may  extend  ;  for  example, 
one  large  ship  may  be  planked  with  4^ 
plank,  a  second  with  4  inch,  while 
a  third  may  have  but  3 \  inch  plank  on 


her  bottom.  There  is  another  fact 
that  should  not  be  forgotten  in  connec- 
tion with  this  subject:  the  strength  of 
Jersey  oak  plank  to  tin;  ordinary  yellow 
pine,  is  as  6  :  5.  Hence  it  is  clear  that 
a  ship  having  5  inch  oak  wales  to  be 
equally  strong,  should  have  6  inch  pine 
wales.  In  order  to  determine  the  re- 
quired displacement  of  a  ship  to  carry 
a  given  number  of  tons,  first  bring  the 
tons  the  ship  is  to  carry  into  cubic  feet, 
add  to  this  the  weight  of  the  ship,  and 
from  the  product  subtract  the  cubical 
contents  of  the  planking,  keel,  stem 
and  post  ;  now  let  D'  be  the  displace- 
ment in  cubic  feet,  planking  included  ; 
D  the  cubical  contents  of  the  bottom, 
without  the  plank  ;  N  the  number  of 
tons  the  ship  is  to  carry,  or  the  num- 
ber of  cubic  feet  contained  in  the 
amount.  N=^?=35,2  cubic  feet  of 
sea-water  contained  in  a  ton,  (we,  how- 
ever, will  find  that  35  feet  per  ton  will, 
under  ordinary  circumstances,  be  quite 
as  well  adapted  to  our  calculations,  in- 
asmuch as  the  river  water,  though  salt, 
is  less  buoyant,  and  approximates  near- 
er the  latter  than  the  former  number.) 
If  the  ship  is  to  be  built  of  oak,  '-  D' 
will  equal  Nx35,2  ;  therefore  D'=5X 
35,2xN  the  number  of  cubic  feet=the 
whole  cubical  displacement  with  the 
plank  on  ;  from  this  subtract  the  plank- 
ing, say  iV,  the  displacement  of  the  bot- 
tom plank  excluded,  the  result  will  be 


MARTNE  AND    NAVAL    ARCHITECTURE. 


2S9 


D=D'—TvD=H=D'o1 D=Hxfx35,2 
xN  cubic  feet.  Should  a  greater  ca- 
pacity be  required  from  the  same  di- 
mensions and  model,  we  may  elevate 
the  load  water-line,  and  take  the  cubi- 
cal contents  of  the  space  contained  be- 
tween the  former  and  the  contemplated 
lines  of  flotation,  remembering'  that  the 
plank  should  be  taken  in  connection 
with  the  contemplated  increase  of 
depth. 

Assuming  that  enough  has  been  fur- 
nished pertaining  to  the  theory  or  sci- 
ence of  building  ships  in  this  chapter, 
we  shall  enter  at  once  upon  the  legiti- 
mate subjects  pertaining  thereto.  We 
have  endeavored  to  bring  with  us  in 
our  delineations  on  the  floor,  all  the 
operations  of  the  mould  loft  save  one, 
viz.,  the  taking  off  the  ship  ;  this  should 
never  be  neglected,  but  in  all  cases  the 
tables  of  the  vessel  should  be  taken  oft' 
the  floor  after  the  whole  work  is  proven. 
From  these  tables,  we  can  make  a  model 
exactly  like  the  ship,  and  what  is  vastly 
of  more  importance  in  case  of  fire, 
we  may  be  able  from  these  tables  to 
replace  the  moulds,  even  though  loft, 
model,  and  moulds  were  burned.  A 
ship-builder  would  be  placed  in  an 
awkward  position,  if  after  the  frame  of 
his  ship  was  half  worked  out,  his  model 
and  moulds  and  loft  were  burned  up,  and 
he  had  taken  no  tables  from  the  floor, 
he  would  find  it  a  difficult  matter  to  fin- 


ish his  ship  like  the  original  design. 
Hence  we  say,  the  taking  off  the  tables 
should  never  be  neglected,  even  until 
the  moulds  were  made,  for  this  reason  : 
when  we  begin  to  make  moulds,  we 
find  the  floor  occupied,  besides  the 
lines  continue  to  grow  dim  as  we  pro- 
gress in  making  moulds.  In  taking  off 
the  tables,  we  should  not  only  take  off 
the  lines  from  square  frames,  but  we 
should  take  off  the  angles  of  the  diaeo- 
rials  from  the  body-plan,  and  the  an- 
gles of  the  cants  from  the  half-breadth 
plan,  scantling  size  of  the  frames,  sid- 
ing size  of  the  stem,  keel  and  post  ;  in 
a  word,  we  should  take  off  all  that  may 
be  required  to  replace  our  work  on  the 
floor,  and  then  it  would  be  no  difficult 
matter  to  build  a  second  ship  like  the 
first. 

Among  the  first  operations  towards 
the  construction  of  a  ship,  is  that  of 
laying  the  keel.  This  is  to  the  ship 
what  the  back-bone  is  to  the  human 
skeleton.  The  timber  composing  the 
keel  is  usually  of  white  oak  ;  some- 
times, however,  a  kind  of  timber  called 
sweet  gum  is  used  for  small  vessels 
that  are  to  be  iron-fastened,  on  account 
of  the  salutary  influence  it  exerts  on 
iron,  which  may  be  driven  into  it.  Iron 
bolts  are  preserved  from  rust  in  this 
kind  of  timber  ;  this  timber  is  in  tex- 
ture similar  to  elm,  of  a  reddish  color  ; 
it  is  too  soft   and  flexible   for  the  keel 


37 


290 


MARINE    AND    NAVAL    ARCHITECTURE. 


of  ships,  and  will  not  hold  copper  bet- 
t'e'r  than  oak.  Much  may  be  said  of 
the  size  and  manner  of  putting  the  keel 
together  ;  its  siding  size  may  and 
should  be  determined  on  the  model,  or 
when  transferring  the  lines  to  the  floor. 
A  just  medium  for  the  siding  size  of 
the  keel  is  found  in  the  size  of  the  floors 
in  the  throat.  With  regard  to  the 
depth  of  the  keel,  the  trade  and  de- 
scription of  the  vessel  must  partially 
determine  this ;  for  large  ships  the 
keel  cannot  be  obtained  of  sufficient 
depth  in  the  single  log  ;  in  all  cases 
where  it  must  of  necessity  be  of 
little  depth,  the  keelson  should  be  of 
more  than  ordinary  depth.  In  pre- 
paring the  keel  when  in  two  depths  of 
logs,  care  should  be  taken  to  have  the 
scarphs  clear  of  each  other ;  and  we 
will  take  occasion  here  to  remark,  that 
the  prevailing  custom  of  making  the 
upper  nibs  of  sufficient  depth  to  clear 
the  rabbet,  is  entirely  wrong.  It  is 
very  generally  supposed  that  the  nib 
of  the  scarph  cannot  be  made  tight  un- 
less a  stopwater  can  be  inserted  at  the 
lower  edge  of  the  garboard  seam  ;  this 
is  quite  unnecessary,  and  not  only  so, 
but  weakens  the  keel ;  even  when  the 
base  line  is  represented  in  the  top  of 
the  keel,  a  three  inch  nib  is  all-suffi- 
cient, and  furnishes  more  strength  than 
a  nib  of  larger  size  ;  when  the  floors  let 
over  the  keel,  and,  as  a  consequence, 


the  base  line  is  below  the  top  of  the 
keel  an  amount  equal  to  what  the 
floors  are  let  down  ;  the  nibs  may 
then  be  less  than  three  inches  ;  the 
stop-water  may  then  be  put  in  the  low- 
er corner  of  the  nib,  and  the  butt  of 
the  nib  opened  with  a  cut  of  the  cross- 
cut saw,  and  caulked  with  rope  yarns 
solid  from  the  stop-water  up.  It  should 
be  borne  in  mind  that  upon  the  stop- 
water  we  must  depend  ;  for  if  the  ves- 
sel gets  ashore,  and  is  hogged,  the 
caulking  fails  to  keep  out  the  water, 
and  the  stop-water  being  at  the  out 
edge  of  the  seam,  fails  to  accomplish 
the  purpose  for  which  it  was  designed, 
inasmuch  as  the  water  works  in  above. 
We  speak  understandingly  on  this  part 
of  the  operation,  having  been  more 
than  once  engaged  in  remedying  this 
evil.  No  matter  how  many  stop-waters 
are  put  into  the  seam  of  a  scarph,  the 
upper  one  should  be  in  the  corner,  and 
that  corner  should  be  at  farthest  half 
way  up  the  garboard  seam  of  a  six 
inch  garboard ;  in  a  word,  the  whole 
scarph  should  be  caulked,  and  stop- 
waters  put  in  at  intervals.  These  re- 
marks on  the  size  of  the  nib  will  ap- 
ply equally  well  to  the  scarph  of  the 
stem.  In  a  large  keel  where  there  are 
a  number  of  scarphs  to  be  cut,  it  is  a 
saving  of  time  to  make  a  mould  for 
them  ;  keel  scarphs  are  usually  from 
5   to  8   feet  long,  and    have    what    is  , 


MARINE    AND    NAVAL    ARCHITECTURE. 


291 


termed  a  hook  in  the  middle  of  their 
length.  A  custom  has  prevailed,  and 
not  without  sufficient  reason,  of  having 
the  lower  side  of  the  keel  shod  with  a 
4,  5  or  6  inch  plank  in  short  lengths; 
the  ohject  is  mainly  to  protect  the  main 
keel  in  case  the  ship  gets  ashore,  in 
which  case  she  may  escape  farther 
damage  than  would  accrue  from  the 
loss  of  one  or  more  pieces  of  the  shoe. 
The  custom  has  prevailed  until  within 
some  few  years' of  putting  on  the  shoe 
after  the  floor  and  keelson  bolts  were 
all  driven  and  rivetted,  and  we  know 
of  no  good  reason  why  the  practice 
should  have  been  even  partially  aban- 
doned ;  it  is  still  adhered  to  in  the 
Navy. 

The  keel  being  about  to  be  laid  upon 
blocks  sufficiently  near  each  other  to 
prevent  sagging  between  them,  we  will 
refer  toour  remarks  made  upon  thepro- 
priety  of  laying  it  with,  a  sag  in  its 
whole  length,  on  page  118.  While 
the  keel  is  being  prepared,  the  floors 
are  being  worked  out  ;  the  stem  and 
stern  frame  are  also  being  put  together. 
The  union  of  stem  and  keel  takes  place 
on  the  top  of  the  keel  in  ships,  but  we 
have  seen  a  number  of  brigs  and 
schooners  on  which  the  scarph  was 
cut  on  the  lower  side  of  the  keel ;  in- 
deed, the  practice  is  quite  common  in 
Baltimore.  It  is  adopted  to  save  the 
expense  of  a  crooked  stem,  which  costs 


more  than  the  straight  one.  The  stem 
with  a  root  to  scarph  on  the  keel,  we 
think  preferable.  The  practice  is  not 
universally  adhered  to  as  in  this  city,  of 
laying  out  the  scarphs  of  stern  post 
and  keel,  and  not  putting  them  to- 
gether before  raising.  We  have  seen 
the  keel  canted  down,  and  the  scarphs 
put  together  of  both  stem  and  post, 
and  the  dead-wood  mould  applied  to 
determine  the  rake,  and  to  make  a  sure 
fit  of  the  scarphs.  We  say  that  the 
mechanic  has  but  little  confidence  in 
his  marks,  who  cannot  lay  off  both  the 
scarph  of  the  stem  and  post,  and  know 
that  they  will  not  only  fit  without  a 
second  trial,  but  that  the  rake  will  be 
as  on  the  floor.  It  seems  to  us  that 
nothing  can  be  more  simple  ;  the  base 
line  runs  across  the  keel  or  the  stem, 
and  is  also  found  on  the  keel;  the  frames 
are  also  marked  on  the  keel  and  on  the 
stem  ;  hence  it  must  be  clear  that  to 
bring  the  frames  to  compare  in  their 
proper  distances  apart,  and  the  base 
line  to  continue  in  its  course  from  the 
keel  to  the  stem,  is  no  difficult  matter. 
We  have  alluded  to  the  scarph  of  the 
stern  post ;  it  is  comparatively  a  recent 
practice  to  select  a  piece  of  timber 
having  a  root  attached  for  a  stern  post 
similar  to  that  of  the  stem  ;  the  amend- 
ment is  a  wholesome  one.  The  former 
practice  of  mortising  the  heel  of  the 
post  into  the  keel,  is  seldom  practised 


292 


MARINE    AND    NAVAL    ARCHITECTURE. 


on  ordinary  sized  vessels.  Assuming 
the  keel-to  be  on  bloeks  and  set  straight 
transversely,  and  properly  secured  with 
cleets  on  the  cap  blocks  to  prevent  its 
being  shifted  by  any  casualty,  it  will  be 
seen  by  reference  to  Plate  15,  that  the 
keel  is  tapered  the  siding  way  at  the 
forward  end ;  in  other  words,  the  side 
line  is  brought  nearer  the  centre  on 
both  the  stem  and  keel  as  they  ap- 
proach the  fore  foot  or  the  place  of 
union.  The  practice  is  quite  common 
of  continuing  the  keel  and  stem  the 
same  size  in  their  whole  length  on  all 
description  of  vessels. 

Having  already  treated  this  subject 
at  some  length,  we  need  only  say,  that 
if  we  have  tapered  the  keel  on  the  floor 
we  may  transfer  the  settings-off  to  the 
keel,  and  bring  it  to  its  proper  size. 
The  dead-wood,  it  will  be  remembered, 
will  be  compared  with  the  keel,  if  we, 
in  laying  off  the  cants,  have  adhered  to 
the  tapered  side-line,  and  we  will  here 
remark,  that  inasmuch  as  there  must 
be  a  side-line  taken  for  every  cant,  it 
is  just  as  easy  to  take  it  off  from  the 
tapered  side-line  as  from  the  parallel 
one.  Our  remarks  apply  particularly 
to  sharp  vessels  ;  in  other  words,  the 
tapered  keel  is  more  especially  design- 
ed for  sharp  vessels,  and  applies  only 
to  the  forward  end  commencing  in  the 
usual  vicinity  of  the  forward  square 
Inline,  or  at  the  commencement  of  the 


dead-wood, — the  starting  point,  how- 
ever, must  be  consequent  upon  the 
sharpness  of  the  vessel.  We  have  de- 
signated a  point  far  enough  aft  for  the 
sharpest  vessel.  With  regard  to  the 
top  of  the  keel,  it  is  not  absolutely  ne- 
cessary that  it  should  represent  the 
base  line.  If  we  have  a  surplus  of 
timber  in  the  upper  log  of  which  the 
keel  is  formed,  we  may  strike  a  base 
line  on  the  sides  of  the  keel  at  the  pro- 
per height,  and  let  the  surplus  be  con- 
sidered as  dead-wood  the  whole  length, 
reducing  the  part  over  which  the  floors 
are  placed  to  a  definite  height,  say 
one  or  two  inches,  which  will  be  cut 
out  of  the  floors,  or  we  may  trim  off 
the  top  of  the  keel  to  the  base  line  the 
length  of  space  covered  by  floors  or 
square  frames.  This,  however,  would 
be  detrimental  to  the  ship,  unless  we 
supply  its  place  with  a  thin  piece  of 
dead-wood,  which  is  sometimes  done. 
The  object  of  this  is,  that  in  case  the 
keel  should  be  entirely  carried  away 
by  the  vessel  getting  on  shore  or  other- 
wise, then  this  piece  of  dead-wood  is 
supposed  to  remain  (being  in  a  separ- 
ate piece)  and  prevent  the  ship  from 
sinking.  This  is,  perhaps,  a  sufficient 
reason  for  taking  this  course  with  the 
top  of  the  keel  ;  at  any  rate  the  floors 
should  let  over  the  top  of  the  keel,  and 
the  line  at  which  they  stop  on  the 
moulding  edge,  is  the  base  line  on  the 


MARINE    AND    NAVAL    ARCHITECTURE 


293 


keel,  and  in  its  continuance  up  the 
stem  and  post,  is  the  same  identical 
line,  although  custom  has  called  it  by 
another  name.  We  have  given  it  a  name 
as  near  as  may  be  to  the  same  ;  we 
have  denominated  this  line  in  its  con- 
tinuance the  margin  line. 

It  is  usual  and  proper  to  cut  the  rab- 
bet on  the  stem  and  post  before  raising 
them  ;  this  may  be  extended  within  a 
few  feet    of  the  scarphs  from   above. 
For  the  manner  of  putting  these  parts 
together,    see  the    respective    articles. 
Assuming  the  keel  to  be  laid  at  a   de- 
scent of  for  a  ship  f  of  an  inch  to  the 
foot,  and  the  stem  and  stern  frame  to 
be  in  their  place,  or  raised  on  the  keel, 
and  the  frames   marked  on  the  side  of 
the  keel,  as  on  the  floor  of  the  loft ;  the 
faces  of  the  floor  timbers  may  also  be 
placed   at  those  stations,  remembering 
that  0  is  in  the  after  body,  and  its  face 
should  be  forward,  while  those  of  the 
fore  body  should  face  aft ;   as  a  conse- 
quence more  space  will  be  required  be- 
tween   ®   and  A,  than   between  other 
frames,  by  the   thickness  of  the  chock 
designed  to  be   put   between  the  floor 
and   first   futtock,  or  the   half  floor,  as 
the  case   may  be.     By   the  half  floor 
timber,  we-  mean    a  floor  timber   half 
the  length  of  the  usual  floor,  crossing 
the  keel,  and  of  the  same  moulding  size 
as    the    regular    or    full    length    floor. 
This  practice   of  placing  two   sets  of 


floors  across  the  keel,  is  of  recent  ori- 
gin, and  is  consequent  upon  the  great 
difficulty  in  obtaining  first  futtocks  of 
sufficient  length,  size  and  crook  for 
ships  of  the  largest  class ;  both  for 
steamers  and  those  intended  for  freight- 
ing purposes.  This  we  regard  as 
a  welcome  improvement,  inasmuch 
as  it  rids  the  keel  of  the  range  of 
butts  with  which  it  was  covered  un- 
der the  old  system. 

But  a  few  words  seem  to  be  neces- 
sary in  relation  to  the  manner  of  rais- 
ing the  frames,  as  being  immediately 
connected  with  the  custom  of  placing 
the  floors  in  their  upright  position 
across  the  keel.  The  manner  we  have 
described  contemplates  a  practice  that 
has  prevailed  for  many  years  in  this 
city,  and  to  which  there  can  be  no  se- 
rious objection,  provided  the  ship  has 
half  floors  ;  we  allude  to  the  prevailing 
custom  of  raising  the  frames  from  each 
side  of  the  ship  transversely,  or  in  half 
frames.  When  this  method  is  adopted, 
the  floors  are  placed  across  the  keel  to 
their  proper  stations,  then  levelled  and 
let  down  ;  by  this  we  mean,  that  they 
are  so  fitted  that  each  floor  is  in  itself 
not  only  level,  but  fits  solid  on  the  keel 
before  bolting.  We  have  sometimes 
seen  alternately  every  other  floor  bolted 
to  the  keel  with  a  single  bolt,  and  the 
remaining  floors  left  without  bolts  un- 
til the   keelson   was  in  its  plaee  ;   w  e, 


294 


MARINE    AND    NAVAL    ARCHITECTURE. 


however,  deem  the  single  bolt  insuffi- 
cient to  hold  the  floor  timber  and  keel 
securely  together,  particularly  of  cop- 
per;  there  should  be  a  bolt  in  every 
floor  and  half  floor,  (if  the  vessel  has 
them,)  connecting  them  with  the  keel 
independent  of  the  keelson.  It  does  not 
follow,  however,  that  all  the  bolts 
should  go  through  the  keel,  particular- 
ly if  the  keel  is  deep  ;  those  connect- 
ing the  half  floors  to  the  keel  need  ex- 
tend but  a  short  distance  into  the  keel 
below,  a  depth  equal  to  that  of  the  floor 
itself  in  the  throat.  While  the  floors 
are  being  bolted,  the  ribbands  may  be 
run  a  few  inches  below  the  floor-head 
sirmark,  and  a  shore  fitted  with  what  is 
termed  a  bird-bill  over  the  edge  of  the 
ribband  to  at  least  every  other  floor  ; 
these  shores  will  regulate  the  entire 
floor  surface,  and  are  assumed  to  be 
sufficiently  strong  to  bear  the  entire 
weight  of  the  frames  when  raised  :  if 
not,  they  should  be.  The  floors  being 
bolted,  their  throats  may  be  made  fair 
(by  running  lines  directly  over  the  sides 
of  the  keel  with  a  stiff  batten  ;  after 
setting  up  at  intervals  the  proper  depth, 
the  keelson  being  thus  prepared)  by 
the  adze,  may  be  put  in  its  place, 
either  by  skids  over  the  side,  or  by  hoist- 
ing them  in  at  the  bow  or  stern.  The 
keelsons  should  be  arranged  and  fully 
prepared  on  the  ground,  and  when  this 
is  done,  as  it  should  be,  it  is  only  ne- 


cessary to  put  them  in  their  place  and 
bolt  them.  The  practice  of  working 
the  keelsons  out  a  second  time  in  the 
hold,  is  wrong;  once  is  enough,  but  it 
has  become  a  practice  so  common  to 
half  do  this  part  of  the  work,  that 
it  almost  invariably  requires  to  be  done 
twice.  We  mean  by  this  what  we  say  : 
that  in  the  first  place  the  throats  of  the 
floor  are  inequitable  and  the  keelsons 
unfair,  (although  enough  labor  has  been 
spent  to  make  them  correct ;)  hence 
it  must  be  quite  clear  that  the  keelsons 
must  be  fayed  after  they  are  inboard  ; 
neither  do  we  mean  by  our  remarks, 
that  the  edges  only  are  to  fay,  as  is  too 
often  the  case  ;  and  while  upon  this 
point,  we  may  add,  that  it  not  only  costs 
less,  but  makes  a  better  job  to  put  a 
heavy  piece  of  timber  in  its  place  but 
once  ;  and  we  will  further  add,  that 
there  is  no  piece  of  timber  that  belongs 
to  a  ship  of  any  considerable  size,  but 
may  be  made  to  fit  on  the  first  trial. 
It  is  true,  that  it  may  not  be  regarded 
as  cheaper  in  all  cases,  but  we  say  (and  i 
understandingly  too)  that  all  keelsons, 
dead-woods,  riders,  breast-hooks,  &c, 
may,  and  indeed  should,  be  made  to 
come  to  their  place  the  first  cut.  The 
great  secret  in  accomplishing  this  is 
using  a  fair  but  stiff  batten  and  dub- 
bing light ;  where  it  is  necessary  to 
make  a  mould,  let  the  side  that  is  to 
be  applied  be   made  to  fit ;   mark  the 


MARINE    AND    NAVAL    ARCHITECTURE. 


295 


bevelling  spots,  and  take  the  bevels  with 
care,  and  directly  square  from  the  face, 
applying  them  exactly  as  taken  upon 
spots  that  are  out  of  winde;  cut  to  the 
marks,  and  the  work  is  performed,  time 
saved,  and  much  heavy  lifting  avoided, 
which  is  more  injurious  to  operatives 
than  the  work  itself.  We  will  conclude 
these  remarks  by  adding,  that  if  after 
our  first  cut  the  timber  does  not  fit,  we 
may  rest  assured  there  is  carelessness 
somewhere,  as  the  foregoing  rules  have 
no  exceptions. 

It  is  unnecessary  to  follow  the  keel- 
sons farther  than  show  them  in  their 
place,  as  Plate  8  will  do.  The  scarphs 
should  be  kept  apart  as  far  as  possible, 
and  apart  from  those  of  the  keel ; 
in  a  word,  the  best  distribution  should 
be  made  for  strength  in  arranging  the 
scarphs.  If  the  keelson  be  in  two 
depths  it  should  be  securely  bolted  with 
through  bolts  of  copper ;  and  where 
the  bolts  are  long,  we  would  recom- 
mend two  drifts  ;  the  first  tier  being 
securely  fastened,  the  upper  tier  may 
be  principally  fastened  to  the  first  with 
iron  bolts,  reserves  being  made  in  the 
first  tier  for  some  copper  bolts  to  go 
through  the  whole.  Our  reasons  for 
using  iron  in  the  upper  tier  of  keelsons, 
may  be  found  in  the  fact,  that  iron 
bolts  are  stronger,  and  being  above  the 
bilge  water  that  may  remain  in  the 
vessel,  are  not  subject  to  the  corrosive 


influences  of  rusfuidre  than  in  many 
other  parts  where  iron  is   used.  ' 

We  have  shown,  in  connection  with 
the  expositions  connected  with  Plate 
8,  that  the  keelsons  may  and  should 
form  a  part  of  the  dead-wood  ;  the 
height  of  which  is  determined  by  the 
scantling  size  of  the  cants  at  the  heel. 
It  may  be  well  to  remark  here,  that  the 
practice  of  putting  in  the  keelsons  be- 
fore raising  the  ship,  has  been  con- 
tinued for  years,  even  when  the  ship 
had  no  half  floors,  and  the  heels  of  all 
the  first  futtocks  landed  on  the  keel. 
We  deem  it  wrong,  however  long  con- 
tinued, inasmuch  as  the  heels  of  the 
first  futtocks  must  be  reduced  smaller 
than  the  size  of  the  floor  in  the  throat, 
or  they  cannot  be  forced  under  the 
keelson,  and  after  they  are  in  their 
place  they  are  loose,  and  too  often  fit 
neither  above  nor  below  ;  in  a  majority 
of  cases  the  keelsons  should  be  kept 
out  until  the  ship  is  raised ;  and  when 
they  are,  it  usually  follows  that  the 
cants  are  kept  behind  the  square 
frames  in  consequence  of  the  inability 
to  cut  the  boxes  for  their  heels,  unless 
the  dead-woods  are  put  in  and  the 
keelsons  over  the  floors  kept  out. 
Further  remarks  upon  the  dead-woods 
and  keelsons  are  unnecessary.  It  may 
be  assumed  that  the  square  frames  are 
being  put  together,  and  likewise  the 
after  cants,  when  preparations  may  be 


296 


MARINE   AND    NAVAL    ARCHITECTURE. 


madq.  for  raising  the  frames  with 
shears.  In  the  meantime  the  heels  of 
the  second  futtocks  are  being  laid  out 
and  cut  off  to  fit  the  heads  of  the  floors  ; 
the  frames,  of  course,  lying  with  the 
second  futtock  side  up,  it  is  necessary 
to  perform  the  same  office  to  the  first 
futtock,  when  the  ship  has  half  floors. 
If  proper  care  is  taken,  the  butts  may 
be  cut  exactly,  so  that  scarce  a  cut 
will  be  necessary  after  the  frames  are 
raised.  If  the  ship  is  large,  the  first 
futtocks  may,  and  indeed  should  be  put 
in  their  place  singly,  without  the  rest 
of  the  frame  ;  this  may  be  done  whether 
the  ship  has  half  floors  or  not ;  and 
when  it  is  done,  the  keelsons  may  be 
put  in  before  the  frames  are  raised,  with 
the  utmost  propriety,  inasmuch  as  the 
course  may  be  faired  over  the  heels  of 
the  futtocks,  and  the  keelson  made  to 
fay  solid  over  the  whole.  When  the 
first  futtocks  are  thus  raised  singly,  it 
is  pre-supposed  their  heads  are  cut  off 
square  from  a  given  angle  vertically, 
and  the  same  from  the  face  longitudi- 
nally. We  may  presume  that  the 
frames  are  ready  for  raising;  and  in  or- 
der to  accomplish  this  part  of  the  work 
smoothly,  we  should  commence  with 
the  after  cants,  under  the  heel  of  each 
one  of  which  a  cleet  should  be  spiked 
on  the  dead-wood,  and  as  we  shall  fol- 
low on  with  the  square  frames,  they 
may  be  canted  up,  and  the  heels  of  the 


futtocks  of  each  frame  placed  over  the 
floor  ribband  in  its  proper  berth.  In 
raising  the  cants,  the  heel  should  be 
entered  in  the  box,  and  the  chain  placed 
on  the  frame  in  which  to  hook  the 
tackle,  near  two-thirds  of  the  length  of 
the  frame  from  the  heel ;  and  when  up 
to  its  proper  height,  and  the  heel  in 
the  boxing,  the  frame  may  be  shored 
from  the  ground  and  stay-lathed  from 
the  stern  frame.  If  the  cants  have 
chocks  between  the  timbers,  the  heel  of 
one  of  the  chocks  will  form  a  lodgment 
for  the  head  of  the  shore  ;  if  they  have 
no  chocks,  a  hole  may  be  bored  through 
the  timber,  and  a  set  bolt  inserted  in 
the  same.  The  shears  are  moved  for- 
ward as  the  cants  are  raised,  and 
each  frame  is  shored  from  the  ground 
and  stay-lathed  from  its  fellow.  If  the 
square  frames  are  heavy,  and  the  first 
futtock  appended,  it  is  customary  to 
have  a  shore  in  the  form  of  a  dog  ; 
that  is  to  say,  a  spruce  spar  is  prepared 
of  suitable  length,  10  or  12  feet  long, 
banded  at  the  ends,  and  a  dog-head  in- 
serted in  each  end;  the  points  of  which 
are  made  thin,  and  are  driven  into  one 
of  the  timbers  above  and  the  other  be- 
low the  bilge,  sufficiently  far  to  prevent 
the  frame  from  being  racked  out  of 
shape,  to  which  it  has  a  tendency,  by 
being  subjected  to  two  forces  that  tend 
to  brin<r  the  head  and  heel  of  the  frame 
together — the    heel    on    the    ribband, 


MARINE    AND    NAVAL    ARCHITECTURE 


297 


and  the  head  under  the  influence  of 
the  tackle:  it  is  seldom,  however,  re- 
quired when  the  first  futtock  is  not  ap- 
pended to  the  frame.  It  is  also  neces- 
sary, when  the  first  futtoeks  are  raised 
singly,  to  run  a  ribband  near  their 
heads,  and  render  it  secure  by  support- 
ing it  with  suitable  shores;  the  square 
frames  are  shored  and  stay-lathed  from 
the  adjoining  frame,  as  the  cants.  It  is 
sometimes  the  case  that  the  raising  of 
the  frames  is  continued  without  inter- 
ruption to  the  stein,  and  the  forward 
cants  are  also  raised  ;  the  usual  mode, 
however,  is  to  make  a  separate  job  of 
the  forward  cants.  One  reason  is,  the 
shears  are  found  to  be  troublesome,  and 
a  derrick  preferable  ;  a  second  rea- 
son is,  want  of  room  to  frame  them 
before  the  square  frames  are  removed, 
inasmuch  as  their  shape  alters  so  fast 
that  they  really  appear  to  be  inside  out ; 
and  the  head  of  the  frame  requires  to 
be  placed  next  to  the  keel,  and  a 
heel  tackle  will  be  needed  to  raise  the 
heel  to  its  place.  The  forward  cants 
are  not  usually  raised  until  one  or  more 
tiers  of  staging  is  around  the  ship,  and 
the  harpens  put  on  the  bow.  It  is  ne- 
cessary to  have  one  or  two  diagonal 
braces  either  inside  or  out,  spiked  on 
the  square  frames  to  counteract  their 
inclination  aft,  which  has  been  known 
to  cause  much  mischief  by  the  excess 
of  weight,  causing  the   frames  to  split 


a  stay-lath  and  cant  the  frames  ;  the 
cause  of  the  excess  of  weight  is  found 
in  the  descent  of  the  keel  upon  which 
the  frames  rest. 

There  is  another  method  of  framing 
and  raising,  that  is  deemed  by  many  to 
be  preferable  to  the  manner  described. 
This  operation  combines  the  whole 
frame,  and  requires  a  platform  some- 
what higher  than  the  lower  side  of  the 
keel,  extending  the  entire  length  and 
breadth  of  the  vessel.  Upon  this  plat- 
form the  frames  are  put  together,  the 
one-half  on  each  side,  and  the  floor  in 
the  centre  across  the  keel ;  after  being 
put  together  it  is  raised  to  make  room 
for  another.  The  operation  is  com- 
menced at  ®  and  carried  on  both  for- 
ward and  aft ;  the  frames  are  raised 
with  two  pair  of  shears,  one  pair  on 
each  side,  standing  fore  and  aft,  with  a 
guy  from  one  to  the  other ;  the  cants 
are  raised  in  the  manner  already  de- 
scribed. When  the  latter  method  is 
adopted,  the  cross  spawls  are  put  on 
the  frames  before  raising  them.  For 
large  ships  there  should  be  two  sets, 
and  they  should  be  put  on  the  frame 
at  the  proper  heights  for  putting  on 
the  clamps  of  the  upper  and  lower 
deck,  and  of  sufficient  strength  to  sus- 
tain the  weight  of  two  or  three  of  the 
beams  at  the  same  time.  rJ  nose  spawls 
are  cut  to  the  proper  breadths  of  the 
fiames  at  those  heights  as  taken  from 


38 


298 


MARINE    A  N  D    N  A  V  A  L    ARCHITECTURE, 


the  floor  of  the  loft,  and  may  be  al- 
ternately put  on  every  other  frame,  first 
above  and  on  the  next  frame  below, 
or  first  a  spawl  for  the  upper  deck,  and 
the  next  frame  one  for  the  lower  deck 
staffe.  When  the  frames  are  raised, 
as  first  described,  the  spawls  are  put  on 
the  frames  after  the  wale  stage  is 
around  the  ship,  and  then  only  on  every 
fourth  frame.  Those  fourth  frames  are 
regulated  first  by  being  regularly  spaced 
on  the  several  ribbands,  and  set  up- 
right by  a  plumb-line  from  the  centre 
of  the  spawl  to  the  centre  of  the  keel- 
son ;  the  intermediate  frames  are  regu- 
lated by  dividing  or  spacing  the  rib- 
bands, and  setting  the  frames  forward 
or  aft,  and  canting  as  they  require; 
there  should  be  a  sufficient  number  of 
ribbands,  and  of  sufficient  size  to  hold 
the  vessel  firmly  to  her  proper  shape. 
While  the  spawls  arc  being  put  on, 
stage  being  built,  &c,  the  frames  may 
be  sawed  down  and  bolted.  We  mean 
by  sawing-  down,  running  a  saw  in  the 
butts  at  the  floor,  or  first  futtock  heads  ; 
should  they  require  one  or  more  cuts, 
we  may  have  the  same  guide  for  this 
operation  that  is  furnished  in  framing, 
viz.,  the  sirmarks  or  diagonals. 

A  ship  may  be  said  to  be  regulated 
when  the  stem  and  stern  post  are  found 
to  be  plumb,  and  a  line  extending  from 
the  centre  of  one  to  the  centre  of  the 
other,  and  at  the  same  time  cutting  a 


plumb-line  over  the  centre  keelson,  from 
the  centre  of  all  the  spawl  frames. 
When  thus  bound  in  ribbands,  and 
securely  shored  with  three  tier  of 
shores,  set  up  under  the  ribbands  with 
a  spike  to  prevent  their  heels  from  be- 
ing moved,  the  ship  it  may  be  pre- 
sumed is  fairly  regulated,  and  the  ori- 
ginal temporary  shores  may  be  taken 
away  without  detriment.  Among  the 
first  operations  t^at  should  be  perform- 
ed immediately  after  a  ship  is  raised 
and  regulated,  is  that  of  boring  a  hole 
with  an  inch  and  a  quarter  auger 
through  all  the  butts  of  the  entire 
frame ;  the  direction  of  these  holes 
should  be  diagonally  from  corner  to 
corner  of  the  butt,  half  out  of  each 
timber  ;  that  is  to  say,  a  hole  inserted 
at  the  moulding-edge  on  the  outside 
should  come  through  at  the  bevelline- 
edge  on  the  inside.  The  object  of  these 
holes  is  to  insert  tree-nails  that  are 
well-seasoned  ;  they  need  not,  however, 
be  driven  only  where  they  are  about  to 
be  covered,  either  inside  or  outside. 
The  tree-nails  should  be  prepared  and 
laid  by  to  season ;  and  as  they  are 
wanted,  let  them  be  driven  as  hard  as 
possible.  The  object  of  this  operation 
is  to  obtain  strength,  which  they  do  in 
the  cheapest  and  most  effectual  man- 
ner;  they  do  not  cost  much,  and  are 
far  preferable  to  any  other  kind  of 
dowel  that  can  be  used,  inasmuch  as 


MARINE  AND  NAVAL  ARCHITECTURE. 


299 


there  is  no  chance  for  the  work  ofthe 
frame  at  the  butt  more  than  elsewhere, 
which  is  not  the  case  either  with  the 
English  mode  of  dowelling  the  butt,  or 
of  scarphing  a  chock  across  the  butt. 
It  may  be  fairly  assumed  that  the 
ship  is  now  ready  for  the  various  op- 
erations of  putting'  on  the  wales,  clamps 
for  the  upper  and  lower  decks,  plank 
sheers,  rails,  stern  and  head — all  of 
which  may  be  carried  on  at  the  same 
time,  with  good  management.  It  is 
seldom,  however,  that  the  plank  sheers 
and  rail  are  in  the  same  state  of  ad- 
vancement with  other  parts  ;  not,  how- 
ever, because  it  may  not  be  done  with 
the  same  precision  and  despatch  that 
it  canat  any  subsequent  period.  Our  re- 
marks on  sheering  will  aptly  apply  here; 
it  is  only  necessary  to  determine  how 
the  outside  shall  be  finished,  whether 
with  flush  side  or  with  a  projection. 
We  determine  the  thickness  ofthe  out- 
side plank  by  bending  a  batten  around 
the  ®  frame  on  the  floor  ;  set  oft"  from 
the  moulding-edge  the  thickness  we  re- 
quire  ;  this  will  determine  the  height 
at  which  the  full  thickness  of  the  wales 
are  required;  and  we  may  run  the 
sheer  strake  in  accordance  with  the 
arrangement  thus  made  ;  it  is  best, 
however,  to  run  the  first  strake  as  near 
tin;  sir  marks  as  maybe.  For  running 
the  deck  line,  setting  up  for  the  inside 
of  the  plank,  both   on  the    flare  of  the 


bow  and  on  the  round  of  the  quarter, 
see  our  remarks  on  sheering,  page  140, 
and  onward.  An  idea  may  be  formed 
of  the  usual  manner  of  arranging  the 
clamps,  water-ways,  bilge  strakes,  &c, 
by  referring  to  a  longitudinal  view  of 
the  transverse  section  of  a  ship,  as 
shown  in  Plate  21  ;  the  clamps  of  both 
decks  are  being  put  on,  and  the  beams 
are  often  ready  before  the  ship  is  regula 
ted  ;  hence  it  follows,  that  as  soon  as 
two  or  three  strakes  of  clamps  are 
on,  squared  and  planed  off,  they 
may  be  placed  where  they  belong, 
bolted  at  the  ends  into  the  clamp,  and 
the  operation  commenced  of  faying 
knees  ;  in  the  meantime  the  upper 
sheer  strake  is  being  put  on,  and  tin; 
upper  edge  run  fair  and  left  standing, 
inasmuch  as  it  is  designed  to  seam  to 
the  lower  side  of  the  plank  sheer,  which 
has  more  cant  outboard  than  the  round 
ofthe  beam  would  give  at  the  end  ofthe 
same.  The  beams  are  sometimes  regu- 
lated by  fairing  the  lower  sides  at  the 
centre  ;  but  this  will  not  answer  a  good 
purpose  where  the  beams  show  any 
considerable  difference  between  the 
size  of  the  middle  and  ends  in  the 
moulding  size;  they  will  not  make  a 
fair  line  both  below  and  above.  The 
usual  method  is  to  fair  the  tops  of  the 
beams,  and  if  the  lower  deck  beams 
are  in  first,  they  may  be  shored  from 
the   floors    along   side    of  the    keelson, 


300 


MARINE    AND    NAVAL    ARCHITECTURE 


and  the  upper  deck  beams  may  be 
shored  fair  from  those  of  the  lower 
deck,  remembering  in  both  cases  that 
the  shores  should  be  kept  aside  from 
the  centre,  that  there  may  be  no  mov- 
ing shores  to  put  up  stanchions.  The 
most  efficient  mode  of  fairing  the  tops 
of  the  beams,  is  by  a  ram  line  extend- 
ing the  entire  length  of  the  ship,  and 
hauled  taught  enough  to  barely  touch 
the  high  beams  ;  and  we  will  add,  that 
the  ram  line  is  preferable  to  any  other 
mode  of  spotting  the  beams  before  fair- 
ing oft*  their  tops;  indeed,  we  have 
seldom  seen  ;i  fair  deck  frame  made  so 
by  the  use  of  the  batten,  and  we  know 
of  no  reason  why  the  centre  of  the  deck 
frame  should  not  be  quite  as  fair  as  at 
the  side  of  the  ship.  The  framing  of 
the  deck  should  be  arranged  on  a  board, 
or  a  draft  should  be  made  on  which 
the  hatches,  mast,  partners,  &c,  should 
be  shown  ;  there  should  be  system  in 
the  distribution  of  the  fore  and  aft 
framing  between  the  beams;  the  spaces 
should  be  so  divided  that  the  carlins 
that  come  between  the  beams  may  be 
as  near  of  equal  lengths  as  may  be  ; 
this  can  only  be  done  by  arranging  the 
fore  and  aft  pieces  by  curved  lines.  It 
will  be  seen,  that  if  the  divisions  are 
made  parallel  to  the  centre,  the  out- 
side berths  will  be  variable.  The 
builder  having  the  least  taste  will  at 
once  discover  that  it  will  add  to  the  ap- 


pearance of  the  deck  frame,  be  an  ad- 
vantage to  the  ship,  and  an  economical 
distribution  of  timber,  inasmuch  as  an 
equality  of  lengths  is  a  saving  of  tim- 
ber. 

It  is  sometimes  the  case  that  the 
knees  lap  one  on  the  other,  and  are 
termed,  according  to  their  location, 
lodge  and  bosom  knees  :  the  lodge 
knee  being  fayed  first,  and  being  on  the 
same  side  of  all  the  beams  ;  the  bosom 
knee  being  placed  on  the  opposite  side 
of  the  next  beam,  forming  the  same 
berth.  The  siding  size  of  the  knees 
must  be  proportionate  to  the  size  of  the 
ship  and  of  the  deck  frame.  The  knees 
of  the  upper  deck  of  a  ship  from  1000 
to  1,200  tons,  should  not  be  less  than 
6  inches,  and  those  of  the  lower  deck 
from  7  to  7\  inches.  If  the  ship  have 
three  decks,  the  upper  deck  may  be  less. 
5  to  5^  inches,  which  would  be  heavy 
enough.  It  is  sometimes  the  case  that 
the  beams  of  all  the  decks  are  made 
larger,  and  the  distance  between  them 
somewhat  increased,  and  larger  knees 
used  ;  when  this  mode  is  adopted,  the 
knees  are  abutted  in  the  centre  of  the 
berth,  and  a  bosom-piece  lapped  over 
both  knees,and  the  bolts  driven  through 
the  whole  from  the  outside.  It  will 
be  remembered  that  two  sheer  strakes 
have  been  run,  the  first  the  upper 
wale,  the  second  the  upper  siring,  or 
the  first  strake  below   the  plank  sheer, 


MARINE    AND    NAVAL    ARCHITECTURE. 


301 


and  the  space  between  has  been  thus 
far  left  open  ;  we  will  now  state  the 
reason  why,  viz.  :  to  drive  the  bolts  in 
the  knees  of  the  deck  frame  through 
the  timbers,  as  before  stated,  from  the 
outside.  There  should  be  a  bolt  in  each 
timber,  and  in  some  cases  two  ;  the 
iron  should  correspond  in  calibre  to  the 
siding  size  of  the  knee  ;  I  iron  is  heavy 
enough  for  6  inch  knees,  and  |  per 
inch  for  all  siding  sizes  below  6  inch, 
but  knees  above  6  inch,  should  have 
one-eighth  and  one-sixteenth  added  ; 
this  would  give  for  an  S  inch  knee 
t  iron,  or  one  inch  and  one-eighth  in 
diameter.  Copper  is  in  general  used 
of  smaller  size,  but  we  know  of  no  rea- 
son why  it  should  be,  apart  from  its 
cost.  The  proportions  we  have  given 
will  hold  good  for  any  sized  knee  be- 
low 10  inch  ;  but  it  should  be  remem- 
bered, that  bolts  over  one  and  a  quar- 
ter inches  in  diameter  should  be  driven 
with  a  ram,  and  as  this  instrument  is 
seldom  used,  the  size  of  the  bolt  is  re- 
duced, and  the  number  of  bolts  in- 
creased. Those  large  knees  referred  to 
are  hanging  knees  for  the  lower  decks, 
breast-hooks,  &c. 

Having  extended  our  general  re- 
marks, as  far  as  we  intended,  on  the 
knees  connecting  the  beams  to  the 
sides  of  the  ship,  we  may  add,  that  a 
breast-hook  is  designed  to  till  up  from 
the   clamp  to  the  top  of  the  beam  on 


the  bow,  also  on  the  stern  of  the  lower 
decks,  both  for  the  purposes  of  strength 
and  of  making  a.  landing  for  the  deck 
plank  ;  and  in  all  the  berths  on  the 
bow,  if  the  knees  are  kept  down  to  the 
clamp,  they  should  be  covered  with 
separate  pieces  to  the  height  of  the 
beams  for  receiving  the  deck  plank. 
The  fore  and  aft  framing  is  sometimes 
let  down  below  the  upper  surface  of 
the  beam;  the  principal  object  in  this 
is  to  cut  less  for  the  reception  of  the 
carlin,  and,  as  a  consequence,  very 
nearly  the  same  amount  of  st length  is 
obtained  with  less  timber,  and,  as  a 
matter  of  course,  less  weight.  The 
carlins  as  used  in  most  of  our  freight- 
ing  ships  are  too  deep  for  their  breadth  ; 
a  carlin  4^  deep  by  8  inches  broad,  is 
much  better  in  several  respects  than 
those  of  greater  depth  and  less  breadth; 
first,  the  broad  carlin  is  better  to  butt 
a  plank  on  than  a  narrow  carlin  ; 
again,  it  cuts  less  out  of  the  fore  and 
aft  piece,  and  likewise  out  of  the  knee  ; 
and  in  answer  to  the  only  objection 
that  can  be  made,  viz.,  the  liability  of 
the  spike  going  through,  we  say,  that  (J 
inch  spikes  will  hold  in  yellow  pine  in  a 
majority  of  cases  until  the  head  of  the 
spike  is  drawn  through  the  deck  plank, 
and  this  is  all  that  should  be  required. 
We  are  assuming  the  deck  to  be  '■$'? 
inches  thick  and  plugged  ;  this  leads 
us  to  another  consideration  :    if  the  (» 


302 


MARINE   AND    NAVAL    ARCHITECTURE. 


inch  spikes  will  hold  the  plank  to  the 
carlins,  will  not  the  same  spikes  hold 
the  plank  to  the  beams  ?  Thus  we  are 
led  to  the  conclusion  that  only  one  sized 
spikes  should  be  used  for  both  beams 
and  carlins,  and  there  is  no  liability  to 
mistakes  in  getting  a  beam  spike  into  a 
carlin.  It  may  be  assumed  that  the 
knees  are  all  fayed  and  fastened  ;  the 
fore  and  aft  pieces  all  let  down  ;  the 
combings  of  the  hatches  let  down  ;  and 
here  we  would  add,  that  the  combings 
themselves  form  fore  and  aft  pieces  for 
the  reception  of  the  carlins ;  this  is 
done  by  making  them  thicker  on  the 
part  below  the  beam,  and  rabbetting 
the  part  above  the  beam  ;  the  carlins 
may  be  let  down  and  made  to  compare 
with  the  beams;  and  we  will  add,  if 
we  desire  to  have  a  handsome  deck  be- 
low as  well  as  on  the  top  side,  we  must 
plane  off  the  entire  deck  frame  ;  the 
ridges  left  by  the  adze  between  the 
courses  can  only  be  removed  effectually 
with  the  plane.  We  do  not  mean  by 
this  remark  that  the  edges  of  the  beams 
are  to  be  run  fair  from  spot  to  spot, 
but  the  entire  surface  ;  then  if  the  deck 
plank  are  properly  planed  on  the  bot- 
tom and  edges,  we  may  reasonably  ex- 
pect a  deck  setting  close  to  the  beams 
and  carlins,  and  not  unless  this  course 
is  adopted.  The  water-ways  may  be 
brought  on  board  and  fayed. 

In  our  remarks  on   sheering  it  was 


shown  that  the  sheer  of  the  deck  was 
often  much  less  than  that  of  the  out- 
side; hence  it  follows,  that  when  this 
is  the  case,  the  water-way  cannot  ex- 
tend to  the  bow,  and  commonly  merges 
into  a  strake  of  thick  plank  forward, 
usually  called  sperketting.  From  14  to 
15  inches  is  about  as  deep  as  the  upper 
deck  water-ways  are  generally  made  ; 
those  of  the  lower  deck  are  not  con- 
fined to  any  breadth  or  depth,  but  are 
commonly  made  of  yellow  pine,  and 
sometimes  are  made  of  three  logs  one 
above  the  other,  and  of  diminished 
thickness  above.  We  deem  it  quite 
unnecessary  to  follow  up  in  detail  all 
the  smaller  items  of  those  plain  jobs 
that  come  within  the  range  of  every 
man's  experience  who  has  worked  on 
a  ship.  The  general  outline  is  all  that 
is  needed.  It  is  assumed  that  the  deck 
frame  is  fair  on  both  decks,  and  it  is 
not  assuming  too  much  to  say  that  the 
timbers  also  are  fair  ;  hence  we  say, 
that  if  the  water-ways  are  fair,  and 
have  been  correctly  bevelled,  they  only 
require  putting  in  place  once,  when 
they  will  be  found  to  fit  to  the  place 
they  were  made  for,  and  may  be  bolted  ; 
the  upper  edge  of  the  upper  deck  water- 
way is  designed  to  seam  to  the  lower 
side  of  the  plank  sheer  and  moulding 
their  whole  lengths,  beyond  which  on 
the  bow  the  sperketting  rises  above  the 
deck  and  continues   the    sheer,  as    is 


MARINE    AND    NAVAL    ARCHITECTURE. 


303 


shown  on  the  outside.  The  plank  sheer 
in  its  whole  width  extends  no  farther 
than  the  stanchions  are  single  ;  the 
whole  frames  designed  for  solid  bul- 
warks make  an  end  of  the  plank  sheer  ; 
a  moulding,  however,  is  continued 
around  the  bow  both  out  and  inside, 
likewise  aft,  if  the  ship  have  poop  deck 
and  solid  bulwarks.  Before  the  plank 
sheers  can  be  laid  out,  the  stanchions 
require  to  be  made  fair,  and  the  scant- 
ling size  reduced  to  a  suitable  taper. 
It  is  important  to  know,  before  tapering 
the  stanchions,  the  siding  way  on  which 
side  the  taper  is  to  be  made,  else  we 
may  be  unable  to  get  the  plank  sheer 
over  the  head  of  the  stanchions.  The 
most  ready  mode  of  determining  this, 
is  to  lay  a  batten  along  on  the  strake's 
edge  against  the  stanchions,  marking 
the  centre  of  each  stanchion  on  the 
batten,  the  face  side  of  the  bulkhead 
timbers  being  also  marked ;  the  batten 
may  now  be  raised  up  to  the  head  of 
the  stanchions,  and  those  centres 
transferred  to  the  same  ;  half  of  the 
size  of  the  heads  may  be  set  off  each 
side  of  the  spots,  and  the  stanchions 
may  be  thus  reduced  to  the  proper  ta- 
per, and  may  be  done  at  the  same  time 
that  the  clamps  and  strings  are  being 
put  on.  With  regard  to  the  sheer  of 
the  rail,  the  rope  may  be  carried 
around  by  the  sirmarks  when  the  low- 
er sheers  are  set,  or  at  any  subsequent 


period.  It  is  presumable  that  the  sheer 
upon  the  floor  is  to  be  tin*  sheer  of  the 
ship;  if  so,  we  have  only  to  set  off  the 
projection  outside  of  the  moulding  edge 
of  the  timbers,  or  the  line  showing  the 
same.  It  will  be  remembered,  that  in- 
asmuch as  the  bow  flares,  we  require 
more  projection  there  than  elsewhere  , 
the  amount  necessary  may  be  obtained 
by  setting  off  the  thickness  of  the  bul- 
warks square  from  the  timber,  and 
then  measuring  on  a  line  parallel  to 
the  load-line  or  base  what  the  bulwarks 
will  give  on  the  bevel ;  beyond  this  we 
require  the  usual  projection  on  the 
flare  of  the  bow  ;  one  inch  to  one  and 
a  half  is  sufficient.  (It  will  be  observed, 
that  the  same  projection  on  the  out-  ' 
side  all  around  when  measured  on  the 
level,  will  appear  to  be  much  smaller  on 
the  bow  than  midships,  after  the  bul- 
warks are  on.)  The  amount  of  projec- 
tion being  determined,  we  have  only  to 
set  off  on  the  floor  this  amount  outside 
of  the  rail-breadth  ;  run  in  the  line,  and 
we  have  the  outside  of  the  rail  to  which 
the  harpen  mould  may  be  applied,  and 
a  spiling  taken  if  required  ;  that  is  to 
say,  if  the  ship  is  so  finished  that  the 
rail  extends  to  the  knight-heads.  It  is 
sometimes  the  case  that  the  moulding 
only  extends  around  the  bow  as  far  as 
the  oak  bulwarks  extend  ;  when  this 
is  the  case,  it  is  only  necessary  to  take 
a    spiling   from    that     point     aft  ;     the 


304 


MARINE    AND    NAVAL    ARCHITECTURE, 


length  of  the  plank  determined,  and  the 
scarphs  arranged  on  the  floor,  the  width 
of  the  rail  may  be  determined  by  the 
plank  we  have,  or  may  be  able  to  ob- 
tain, not  only  the  shape  of  the  rail  may 
be  determined,  but  the  bevel.  It  is 
quite  as  essential  that  the  shape  of  the 
top  side  of  the  rail  should  be  laid  down, 
as  that  of  the  lower  side;  and  we  will 
add,  that  the  whole  rail  may  and  should 
be  worked  out  and  put  together  on  the 
ground  before  going  on  board  of  the 
ship.  It  is  presumable  that  the  stanch- 
ions  have  been  cut  off  the  length  of  the 
tenon  above  the  line  designed  for  the 
lower  side  of  the  rail,  and  that  the 
stanchions,  and  indeed  the  entire  side- 
line, has  been  moulded  fair,  with  bat- 
tens both  outside  and  inside.  After 
those  lines  have  been  traced,  and 
another  line  run  below  on  the  solid 
bulwarks,  and  trimnied  out  between, 
we  are  ready  for  the  rail,  which  may 
be  brought  on  board,  put  together  again 
on  the  stanchions,  ami  cut  down  to  its 
destined  place,  remembering  that  the 
rail  should  have  sufficient  cant  to  turn 
the  water  outside  of  the  ship,  except 
on  the  bow,  where  it  cants  less,  and  is 
set  to  a  line  straight  across  at  the 
knight-heads.  The  tenons  may  be  cut 
on  the  stanchions  before  the  rail  is  put 
on,  or  they  may  be  laid  out  and  all  cut 
at  the  same  time.  With  regard  to  the 
finish  forward,  the  mouldings,  when  the 


timbers  extend  above  the  main  rail, 
are  worked  out  to  the  width  which  the 
thickness  of  the  rail  would  show  on 
the  face  of  the  timbers,  and  bevelled  to 
compare  with  the  cant  of  the  rail  on 
both  edges,  then  being  steamed,  are 
bent  around.  In  such  cases  the  ship 
has  no  chocks  on  the  bow,  but  the  bul- 
warks are  continued  above  the  main 
rail,  both  inside  and  out,  and  a  smaller 
rail  extends  around  the  forecastle,  and 
is  often  continued  the  entire  length  of 
the  ship,  and  is  known  as  the  hammock 
or  monkey  rail.  The  same  remarks 
are  applicable  aft,  in  the  arrangements 
of  the  poop-deck  ;  the  main  rail  is  con- 
tinued by  a  moulding  the  length  of  the 
poop  deck,  and  the  bulwarks  are  con- 
tinued above  to  the  upper  rail  already 
alluded  to.  Thus  it  will  be  seen,  that 
when  the  rail  is  continued  around  the 
bow,  it  is  also  continued  to  the  stern 
without  interruption.  We  unhesita- 
tingly say,  that  the  rail  of  a  ship  should 
be  worked  out  bevelled,  and  the  scarphs 
fitted  before  going  on  board ;  and  it  is 
much  easier  to  fit  the  work  on  the 
ground  than  on  board  the  ship.  'J1  he 
rabbet  around  the  bow  on  the  lower 
side  of  the  rail,  for  the  reception  of  the 
bulwarks,  cannot  be  cut  complete  be- 
fore the  rail  is  down  to  its  place  with- 
out hazard.  The  scarphs  of  a  rail  should 
be  edge-ways;  and  we  deem  the  key 
scarph   to    be  preferable   to  the    hook 


MARINE    AND    NAVAL    ARCHITECTURE 


305 


scarph  for  rails.  The  thickness  of  the 
rail  demands  our  notice.  Commonly 
a  ship  of  1000  tons  would  receive  a 
rail  of  5  inches  in  thickness  ;  the  plank 
sheer  the  same ;  but  we  would  make 
the  plank  sheer  thicker  than  the  rail, 
for  two  reasons  :  first,  there  is  less  flare 
on  the  bow  at  the  plank  sheer  than  at 
the  rail;  and,  as  a  consequence,  though 
the  plank  sheer  be  the  same  size,  it  will 
appear  to  be  smaller ;  second,  the 
strakes  grow  narrower  as  we  go  up- 
ward, and  consequently  make  the  rail 
appear  heavy  ;  hence  we  say,  that  if 
the  rail  requires  a  thickness  of  5 
inches,  we  would  make  the  plank 
sheer  5?  inches  thick  at  least.  The 
width  of  the  rail  is  variable,  from  12 
to  15  inches,  and  even  more.  We 
cannot  determine  any  particular  kind 
of  finish  for  the  top  work  of  a  ship, 
there  is  such  an  endless  variety,  and 
all  seem  to  be  adapted  to  the  va- 
rious trades  for  which  they  are  intend- 
ed. This,  however,  is  altogether  un- 
necessary ;  the  young  builder  requires 
only  the  general  outline.  We  have 
confined  our  remarks  to  the  manner  of 
building  ships  in  this  city,  which  seems 
to  be  the  standard  for  nearly  all  parts 
of  the  commercial  world.  We  speak 
advisedly,  having  been  called  on  from 
all  parts  of  Europe  for  New- York 
models,  both  with  regard  to  the  form  of 
the  hull,  and  manner  of  doing  work. 


These^  inquiries  are  not  confined  to 
other  countries;  it  is  quite  common 
for  the  ship-builders  of  New-England 
and  other  parts  to  make  a  yearly  tour, 
to  canvass  the  improvements  in  shape, 
proportions,  and  finish. 

It  is  presumed  that  enough  has  been 
said  about  the  plank  sheers  and  rail ; 
it  may  be  only  necessary  to  add,  that 
the  plank  sheer  should  be  laid  out  the 
thickness  of  a  rule  larger  than  the 
stanchion  all  around.  In  placing  the 
rule  staff  for  taking  the  spiling  of  the 
plank  sheer,  care  should  be  taken  to 
see  that  the  edge  of  the  staff*  is  square, 
and  the  upper  side  of  the  staff  is  ex- 
actly at  the  height  at  which  the  top  of 
the  plank  sheer  is  to  come,  and  at  the 
same  cant.  First  take  a  spiling  for  the 
shape  of  the  plank,  and  then  for  the 
stanchions,  first  by  marking  their  sides  ; 
and  then  taking  a  large  pair  of  com- 
passes, setting  them  to  a  definite  size, 
say  they  are  opened  wide  enough  to 
reach  from  the  outside  of  the  stanchions 
to  the  out  edge  of  the  staff,  that  being 
on  the  inside  of  the  stanchions  ;  the 
compasses  may  then  be  applied  to  every 
stanchion,  first  outside  and  then  on  the 
inside ;  that  is  to  say,  apply  one  point 
at  the  outer  corner  of  the  stanchion, 
and  the  other  point  in  the  scribe  made 
for  the  side;  make  a  prick,  and  then 
do  the  same  with  the  inside  ;  this  done 
on  both  sides  of  each  stanchion,  will 


39 


306 


.MARINE    AND    NAVAL    ARCHITECTURE. 


furnish  correct  data  tor  the  holes  for 
the  stanchions;  the  stanchion  deter- 
mines all  the  scarph  that  is  required 
for  plank  sheer  ;  one  nib  will  cut  with 
the  side  of  the  stanchion  on  one  side 
of  the  plank  sheer,  and  the  other  nib 
on  the  opposite  sides  both  of  stanchion 
and  plank  sheer.  They  are  common- 
ly put  over  and  trimmed  fair  on  the 
inside,  taken  off  and  the  moulding 
worked,  when  they  are  put  over  the 
stanchions,  but  not  set  down  and  fast- 
ened until  the  ship  is  fully  salted  ;  sills 
for  the  reception  of  which  are  put  be- 
tween the  timbers  about  the  light  water- 
line,  and  extend  the  entire  length  of 
the  ship  ;  and  in  order  that  the  salt 
may  run  down,  part  of  the  chock  is  re- 
moved. The  heads  of  all  the  timbers 
are  often  sawed  off"  below  the  lower 
side  of  the  plank  sheer,  in  order  that 
the  salt  may  cover  them;  both  the  edge 
of  the  outside  sfrake  and  that  of  the 
water-way  are  presumed  to  have  been 
trimmed  fair,  both  fore  and  aft,  and 
thwartships,  and  at  the  same  time  are 
out  of  winde.  The  plank  sheer  should 
be  bolted  edgewise  through  every 
stanchion,  and  have  at  least  two  bolts 
through  edgewise  between  the  stanch- 
ions  to  prevent  their  being  split.  As  it 
must  be  quite  apparent  that  there  is 
danger,  inasmuch  as  they  have  no  bear- 
ing in  the  centre,  they  should  also  be 
well-fastened  to  the  strake  outside,  and 


the  water-way  inside.  Before  we  leave 
the  top  work,  we  may  show  the  best 
manner  of  putting  on  the  bulwarks  on 
the  bow,  outside  in  particular  ;  they 
are  usually  put  on  of  oak,  and  are 
some  2  inches  thick  if  the  bow  have 
any  considerable  flare  and  is  full;  the 
strakes  should  not  be  over  3  inches  at 
the  after  end  ;  we  can  only  approxi- 
mate the  width,  inasmuch  as  the 
opening  should  be  equally  divided. 
When  an  attempt  is  made  to  put  bul- 
warks on  in  4  to  5  inch  strakes,  it 
makes  a  bad  job  ;  the)'  coak  off  from 
the  timbers,  are  split,  splintered,  and 
broke,  and  are  an  eye-sore  to  a  man  of 
taste.  We  have  seen  bulwarks  put  on 
in  parallel  widths ;  take  for  example 
the  opening  at  the  after  part  of  the 
bulwarks;  divide  the  same  into  12  to 
15  strakes.  as  the  case  may  require  ; 
make  the  strake  the  same  width  its 
whole  length,  and  commencing  above 
putting  on  the  strake  under  the  rail, 
and  continuing  down  until  we  shut  in 
aft,  and  from  thence  to  put  on  strakes, 
shutting  in  on  the  plank  sheer  with 
every  strake  growing  shorter.  If 
this  is  properly  done,  it  is  quite  as 
good  as  if  regularly  divided  all  around, 
and  is  quite  an  item  in  saving  plank ; 
the  extra  width  on  the  luff  of  the  bow 
cuts  plank  to  waste.  The  bulwarks 
should  be  narrow  from  another  con- 
sideration :  the  plank  is  thin,  and  con- 


MARINE    AND    NAVAL    ARCHITECTURE 


307 


sequently  the  shrinkage  is  greater  in 
proportion  to  the  breadth  of  the  same 
when  the  bulwarks  are  wide.  The 
wales  are  assumed  to  be  5  inches  thick, 
we  make  them  usually  7  inches  wide  ; 
now  let  us  see  the  proportionate  width 
for  2  inches  thick,  If  5  :  7  ::  2  we 
have  7x2-=-5=2!  inches  and  nearly  a 
sixteenth  ;  hence  it  is  plain,  that  we 
need  never  be  at  a  loss  to  know  the 
proportionate  width  for  any  thickness 
of  plank  that  is  to  be  weather  proof. 
We  have  more  than  once  seen  oak 
bulwarks  only  2  inches  thick  that  were 
about  as  wide  as  the  wales  should  have 
been.  We  do  not  set  down  7  inches 
as  a  suitable  width  for  5  inch  wales  ; 
we  say  that  narrow  wales  would  be 
better,  and  were  showing-  what  is 
usually  done.  Yellow  pine  plank 
shrinks  much  less  than  oak,  and  it  is 
quite  common  to  plank  first  class  steam- 
ships with  yellow  pine  ;  it  is  equally 
durable,  and  more  buoyant,  and  would 
make  a  difference  of  several  inches  in 
her  draught  of  water,  even  at  the 
same  thickness  as  that  of  oak  ;  but  we 
have  said  that  it  should  be  of  greater 
thickness  to  make  up  the  deficiency 
or  loss  in  strength. 

Having  extended  our  general  re- 
marks on  plank  sheer,  rail,  bulwarks, 
and  wales,  as  far  as  we  designed,  we 
now  go  on  board,  and  commence 
where  we  left   the   deck  frame.      The 


hatches  may  now  be  framed  on  both 
decks.  Our  remarks  in  relation  to  the 
coamings  forming  tin;  fore  amUaft  piece. 
applies  to  the  upper  deck  principally  ; 
the  lower  deck  coamings  are  usually 
low,  barely  enough  to  turn  the  water 
from  the  hatch.  The  usual  fore  and 
aft  piece  forms  the  hatch  on  the  lower 
deck  ;  there  should  be  a  centre  strake 
of  deck  somewhat  wider  than  the  other 
parts;  indeed  the  width  of  two  strakes 
would  be  scarce  too  wide.  This  strake 
should  be  prepared  by  being  planed 
both  sides  ;  it  should  also  be  thicker 
than  the  deck,  inasmuch  as  it  is  de- 
signed for  the  centre  strake,  and  to  re- 
ceive  the  heels  of  all  the  stanchions 
between  decks.  The  middle  of  this 
strake  should  be  laid  to  the  centre  ;  the 
reason  why  it  should  be  thicker  is  to 
prevent  water  from  running  from  one 
side  of  the  ship  to  the  other  that  may 
chance  to  come  in  the  steerage.  It  is 
not  always  the  case  that  it  is  thicker, 
nor  is  it  absolutely  necessary  that  it 
should  be  so.  The  stanchions  may 
now  be  put  up  between  decks,  and  by 
referring  to  Plate  21,  we  shall  discover 
that  they  are  turned,  and  that  the  two 
decks  are  confined  by  a  bolt  passing 
through  the  stanchion  and  both  beams, 
with  a  nut  on  below  the  lower  deck 
beam.  When  the  stanchions  are  up 
between  decks,  and  the  edge  of  the 
water-way  to  which  the  deck  is  to  seam 


30S 


MARINE    AND    NAVAL    ARCHITECTURE, 


is  made  fair,  the  lower  deck  frame  is 
ready  for  the  reception  of  the  deck, 
which  is  commonly  laid  straight  and 
in  parallel  widths  not  to  exceed  6 
inches.  The  upper  deck,  however,  is 
usually  ready  for  being  laid  first,  and 
may  be  so  considered  when  the  hatches 
are  framed,  partners  in  their  place,  bitts 
in,  framing  and  sole  pieces  for  windlass 
bitts  in  their  place.  The  framing  for 
windlass  bitts  usually  consists  of  thick 
yellow  pine,  of  considerable  width,  ex- 
tending over  two  berths,  covered  by  a 
sole  piece  of  equal  width,  and  at  least 
I  inch  thicker  than  the  deck,  through 
which  the  bitts  are  mortised.  We 
have  seen  the  windlass  bitts  of  ships 
that  depended  wholly  upon  the  knee 
that  fayed  on  the  forward  side  of  the 
bitts ;  the  bitts  themselves  extending 
but  2  inches  into  the  sole  piece,  which 
was  the  thickness  of  the  sole  piece 
above  that  of  the  deck,  having  no  ex- 
tra framing  below,  and  there  being  but 
one  beam  to  which  the  knee  could  be 
fastened,  must  depend  upon  the  sole 
piece  principally  for  support  ;  and  yet 
such  ships  have  been,  and  doubtless 
still  are,  insured  as  first  class  ships. 
The  fore  and  main  partners  are  often 
formed  of  mahogany,  of  from  9  to  12 
inches  thick,  in  2  to  3  widths,  and  ex- 
tending from  the  fore  and  main  hatch 
to  the  respective  beams  aft,  and  bolted 
securely  to  the  same,  also    connected 


together  with  bolts  edgewise.  It  seems 
to  be  necessary  to  have  a  very  consid- 
erable thickness  to  the  partners,  inas- 
much as  the  masts,  bitts,  pumps,  &,c. 
going  through  leave  but  little  solidity 
without  considerable  thickness.  As- 
suming the  water-way  seam  to  be  fair, 
we  shall  proceed  to  delineate  the  man- 
ner of  laying  the  upper  deck,  the  beauty 
of  which  consists  more  in  its  fair,  hand- 
somely curved  seams, and  proportionate 
taper,  than  in  the  quality  of  the  plank. 
White  pine  is  preferable  to  other  kinds 
of  timber  for  the  decks  of  merchant 
vessels.  Narrow  strakes  make  the 
best  deck,  for  two  reasons  :  first,  there 
is  less  shrinkage  to  the  narrow  than  to 
the  wide  plank,  and,  as  a  consequence, 
the  deck  will  remain  tight  longer  ;  the 
second  reason  is  found  in  the  firmness 
or  adherence  to  the  beams  of  the  nar- 
row over  that  of  the  wide  deck,  where 
by  some  mistaken  freak,  the  deck  is 
caulked  hard.  The  width  of  the  plank 
should  bear  the  same  proportion  at  dif- 
ferent parts  that  the  deck  does  ;  that 
is  to  say,  if  the  deck  at  the  stern  is  but 
three  quarters  of  the  width  of  the  deck 
midships,  the  plank  should  be  the  same  ; 
in  other  words,  if  the  plank  be  5  inches 
wide  midships,  31  would  be  the  width 
aft,  inasmuch  as  31  inches  an;  three- 
fourths  of  5  inches.  Again,  suppose 
the  width  of  the  deck  at  the  fore  hatch 
is  1  of  the  whole  width,  does  it  not  fol- 


MARTNE   AND    NAVAL    ARCHITECTURE, 


309 


low  that  the  plank  should  be  the  same  ? 
and  that  if  the  plank  were  5  inches 
wide  midships,  it  would  be  but  4|  at 
the  fore  hatch.  We  must  determine 
how  many  strakes  the  deck  will  require 
at  5  inches.  Suppose  the  deck  to  be 
from  water-way  to  water-way  33  feet 

4  inches  wide,  which  at  5  inches  would 
require  80  strakes,  only  half  of  which 
we  require  on  each  side,  now  it  is  plain 
that  the  centre  seam  is  straight,  and 
that  the  curve  gradually  increases  on 
every  strake  as  we  proceed  towards 
the  water-way,  and  we  shall  discover 
that  the  water-way  seam  has  more 
curve  than  any  other  seam  in  the  deck  ; 
this  symmetry  is  brought  about  by  the 
taper  of  the  plank,  as  we  shall  see. 
A  batten  may  be  prepared,  and  the 
half  width  of  the  deck  taken  at  about 

5  places:  1.  at  the  widest  part,  and  2. 
settings-off  forward,  and  an  equal  num- 
ber aft,  and  we  have  the  problem  for 
solution  at  once  at  each  of  the  settings- 
off.  First,  if  the  midship  breadth,  being 
16  feet  8  inches,  (which  is  the  half  of 
33  feet  4,)  gives  5  inches  in  40  strakes, 
what  will  the  half-breadth  of  the  next 
setting-off  give?  and  we  may  in  this 
manner  obtain  the  widths  at  the  sev- 
eral settings-off.  We  cannot  adapt 
the  taper  to  the  bow,  and  it  is  not  ne- 
cessary to  take  a  setting-off  forward  of 
the  foremast.  There  are  other  modes 
doubtless  equally  as  good  for  diminish- 


ing a  deck,  one  of  which  we  shall  give  : 
divide  the  space  marked  on  a  batten 
between  the  half  width  taken  at' the 
stern,  and  the  half  width  taken  mid- 
ships, into  as  many  portions  as  there 
are  strakes  in  half  of  the  .deck,  say  20, 
and  number  the  parts  as  widths  in 
inches  and  eighths  ;  for  example,  as  we 
have  shown,  let  the  width  at  the  after 
beam  be  3f ;  the  first  of  those  spots 
should  be  marked  3f  and  TV  ;  the  sec- 
ond 31  ;  the  third  31  and  TV  ;  the  fourth 
4  inches,  and  so  on  in  like  manner  we 
advance  20  sixteenths  from  mark  to 
mark,  and  reach  the  full  width,  viz.,  5 
inches.  It  will  be  understood  that  we 
are  arranging  to  work  out  a  strake  the 
same  width  that  the  whole  deck  is  to 
be,  and  then  this  strake  is  arranged  and 
regulated  with  large  spikes  in  the  fol- 
lowing manner :  take  a  small  batten 
and  make  a  scale  for  an  opening  of 
say  7  strakes,  and  in  order  to  obtain 
this  we  have  but  to  add  the  7  widths 
together,  or  multiply  the  width  of  the 
after  end  by  7,  and  we  have  28i  inches  ; 
we  now  measure  26i  inches  from  the 
square  end  of  a  small  batten,  and  di- 
vide the  space  between  the  261  inch 
mark  and  35  inches  (this  being  the 
whole  width  of  7  strakes  5  inches  wide) 
into  7  equal  parts,  marking  each  spot 
as  follows:  the  first  spot  3}  inches; 
the  second  31  and  TV  inches;  the  third 
M  inches  ;  the  fourth  41  and  TV  inches  ; 


310 


MARINE    AND    NAVAL    ARCHITECTURE. 


the  fifth  4$ ;  the  sixth  41  and  r\  ;  the 
seventh  41 ;  the  eighth  5tV.  We  thus 
discover-  that  we  must  either  »o  into 
fractions  not  found  on  .the  carpenter's 
rule,  or  divide  the  spaee  by  sixteenths, 
inasmuch  as  seven  times  one-eighth 
and  one  sixteenth  make  one  inch  one 
quarter  and  one-sixteenth,  which  is  re 
too  much  ;  this,  however,  makes  no 
difference,  as  we  can  make  the  open- 
ing i  of  the  space  between  5A  and  4? 
less  than  the  spot  at  5  A  calls  for,  and 
we  have  what  we  want.  The  reason 
is  obvious  ;  there  are  t\  difference  be- 
tween the  width  41  and5rV;  conse- 
quently one-third  off  leaves  just  what 
we  want,  viz.,  5  inches.  We  have  se- 
lected an  odd  number  of  strakes  for 
two  reasons  :  first,  that  we  might  make 
the  most  intricate  case  of  division  that 
would  be  at  all  likely  to  occur  perfectly 
plain  ;  our  second  reason  was,  that  we 
might  have  the  shutters  in  the  deck 
properly  distributed  ;  and  we  would 
add,  that  every  fourth  strake  should  be 
a  shutter  if  we  would  have  a  tight  deck. 
Our  batten  being  prepared,  we  must 
apply  it  aft,  the  square  end  against  the 
water-way,  and  tack  the  strake  at  the 
first  spot  ;  here  we  discover  the  strake 
is  3!  inches  wide,  and  that  7  strakes  of 
the  same  width  will  fill  up  the  opening, 
because  7  times  31  make  26t  inches, 
and  that  is  the  distance  of  the  first 
mark  from  the  end  of  the  batten;   the 


after  end  of  the  plank  being  tacked,  we 
shift  the  batten  forward,  and  apply  it 
to  the  opening,  where  we  find  the 
plank  corresponds  in  width  witli  that 
called  for  by  the  next  spot  on  the  bat- 
ten ;  that  is  to  say,  where  we  l\nd  the 
plank  to  be  31  and  iV  inches  wide,  there 
we  set  the  strake  to  the  opening  found 
at  the  second  spot  ;  thus  we  continue 
the  operation  until  the  whole  strake  is 
set  not  only  to  the  widest  place  on  the 
strake,  viz.,  5  inches,  but  the  whole 
distance  forward  as  far  as  the  deck  was 
first  divided  at  the  fore  hatch,  from 
thence  the  strake  may  continue  fair  to 
the  sperketting.  If  the  strake  thus  set 
is  fair,  or  shows  a  fair  outboard  edge, 
we  may  readily  conclude  that  our  di- 
visions are  correct,  and  may  run  off 
any  irregular  swell  the  inboard  edge 
may  show;  the  strake  being  about  what 
we  want,  may  be  fastened.  Due  at- 
tention to  the  manner  of  fastening  is 
quite  essential  ;  for  a  white  pine  deck 
of  not  more  than  5  inches  wide,  one 
spike  in  each  beam  andcarlin  is  enough, 
except  at  the  butts  ;  they  should  be 
crossed  alternately,  first  on  one  edge 
of  the  plank  ;  the  next  on  the  opposite 
edge.  The  same  arrangement  should 
be  made  with  the  beams  and  carlins  ; 
the  spike  should  be  one-third  of  the 
width  of  the  plank  from  the  edge  ;  its 
length  must  be  determined  by  the  thick- 
ness of  the   plank.      Having   fastened 


MARINE    AND    NAVAL    ARCHITECTURE. 


311 


our  first  strake,  we  may  use  the  same 
settings-off'  or  scale  for  another  open- 
ing of  seven  strakes  inboard  from  the 
first ;  this  strake,  it  will  be  perceived, 
forms  less  curvature  than  the  first,  and 
each  strake  must  of  necessity  continue 
to  straighten  as  we  approach  the  cen- 
tre ;  this  strake  being  worked  to  the 
width  called  for,  and  the  opening  set 
by  the  batten,  showing  at  the  same 
time  a  fair  seam  or  edge,  may  also  be 
fastened.  We  now  have  one-half  or 
one  side  of  the  deck  divided  into  three 
principal  openings,  two  of  which  are 
equal.  This  arrangement,  however, 
is  not  arbitrary;  the  last  strake  may 
interfere  with  the  hatches,  as  it  no 
doubt  would.  We  may  divide  again, 
and  take  a  fourth  strake  from  the  first, 
and  having  the  strake  and  opening  to 
agree,  the  strake  may  be  fastened,  and 
another  made  to  seam  to  it  on  each 
side;  so  of  the  first,  this  will  leave  an 
opening  of  one  strake,  which  is  term- 
ed the  shutter ;  the  outside  berth  or 
opening  may  be  divided  by  having  a 
strake  in  the  centre,  and  to  that  centre 
strake  another  on  each  side,  which  will 
(by  adding  another  strake  to  seam  to 
the  water-way)  leave  the  remainder  of 
the  deck  in  shutters  ;  those  openings 
may  be  filled  by  bringing  the  plank  on 
board  with  only  one  edge  planed,  and 
worked  out  to  the  size  of  the  opening 
on   deck,  or  the    size   of  the   opening 


may  be  taken  on  a  batten  and  carried 
to  the  plank.  The  shutter  should  be 
driven  in  tight,  but  it  will  not  answer 
to  make  the  plank  more  than  one-six- 
teenth larger  than  the  opening,  else  we 
will  be  liable  to  shatter  the  plank  in 
driving  down.  It  is  a  common  prac- 
tice to  chamfer  the  shutter  ;  this  is 
wrong,  the  upper  edge  of  the  plank 
forming  the  opening  should  be  cham- 
fered, if  any ;  the  seam  below  should 
be  as  tight  as  possible. 

We  have  said  that  the  divisions  of 
the  openings  were  not  arbitrary ;  we 
will  also  add,  that  the  precise  manner  of 
dividing  is  not  arbitrary.  We  have 
only  shown  the  principle  ;  the  manner 
of  dividing  may  be  left  with  the  prac- 
titioner. We  may  take  such  number 
of  strakes  as  shall  make  an  even  num- 
ber of'eighths,  or  sixteenths,  or  thirty- 
seconds  of  an  inch,  or  we  may  adopt 
the  decimal  mode,  as  shown  on  page 
3  ;  the  principle  is  the  same;where  the 
taper  is  more  gradual  the  marks  or 
settinos-off  on  the  batten  will  be  closer 
together  than  where  the  openings  in- 
crease or  diminish  faster ;  but  again, 
the  same  gradation,  in  fact  the  same 
scale,  applies  equally  to  a  more  or  less 
gradual  taper;  that  is  to  say,  in  adapt- 
ing our  scale  to  an  opening  to  be  filled 
with  a  given  number  of  strakes,  having 
reached  the  largest  part  of  the  opening, 
and  the  opening  begins  to  grow  smaller, 


312 


MARINE    AND    NAVAL    ARCHITECTURE. 


but  in  a  diminished  or  increased  ratio, 
it  makes  no  difference  in  the  scale,  be- 
cause the  opening  is  to  be  rilled  with 
the  same  number  of  strakes  as  the  first. 
The  same  principle  applies  to  the  divi- 
sion of  the  batten  for  planking,  to 
which,  however,  less  attention  is  paid, 
because  ii  is  not  necessary  that  the  plank 
on  the  outside  should  be  of  equal  width, 
but  it  is  very  important  that  the  deck 
should  be  very  nearly  equal  in  the  width 
of  the  strakes.  We  may  adopt  the 
same  mode  in  the  strings,  taking  the 
opening  forward  between  the  strakes 
under  the  plank-sheer  and  the  upper 
wale,  assuming  that  it  was  in  accord- 
ance with  this  width,  or  with  an  equal 
division  of  the  strakes  that  the  first 
strake  was  put  on  ;  assuming  the  open- 
ing to  be  one  of  six  strakes,  or  that  six 
strakes  of  the  same  width  as  the  upper 
one  will  fill  the  opening ;  suppose 
the  opening  forward  to  be  30  inches, 
and  midships  to  be  33  inches,  is  it  not 
plain  that  the  strakes  must  be  5  inches 
wide,  inasmuch  as  6  times  5  are  30  ? 
and  is  it  not  also  quite  as  clear  that 
the  width  midships  must  be  5h  inches, 
inasmuch  as  6  times  5b  are  equal  to 
33  inches  ?  Thus  we  discover  that  on 
a  batten  33  inches  long,  we  may  make 
a  scale  by  which  to  determine  the 
widths  of  the  strings,  provided  the 
opening  be  as  we  have  assumed  it  to 
be  ;  hence  it  is  plain,  that  if  an  open- 


ing of  30  inches  requires  6  strakes  5 
inches  wide,  and  33  inches  also  re- 
quires 6  strakes  of  5J  wide,  it  must  be 
equally  clear  that  if  the  space  between 
the  30  and  the  33  inch  mark  be  equal- 
ly divided  into  4  parts,  that  each  of  the 
marks  will  represent  the  width  required 
to  fill  the  opening  in  6  strakes  at  any 
place  where  the  opening  corresponds 
with  the  mark.  For  example,  we 
make  the  first  mark  from  the  square 
end  30  inches  ;  at  30*  inches  we  mark 
the  batten  5£ ;  at  the  second,  2  or  li 
inches  we  mark  5i;  at  the  third,  S  or 
21  inches  we  mark  5| ;  at  the  fourth, 
4  or  3  inches  we  mark  5i  inches  ;  now 
does  it  not  appear  plain,  that  the  six- 
eighths  of  space  between  the  spots  re- 
present the  six  strakes  ?  and  it  would 
make  no  difference  whether  it  were 
sixteenths,  eighths,  or  quarters  of  the 
inch  of  space  between  the  spots  farther 
than  this.  The  closer  the  spots  on  the 
batten,  the  jiearer  will  be  the  settings- 
off  or  the  widths  furnished  to  line  the 
plank  by  ;  if,  however,  the  spots  or 
widths  are  given  within  5  feet  of  each 
other,  it  is  near  enough.  We  may  pre- 
sent this  subject  in  another  form,  to 
which  we  have  referred ;  the  widths 
may  be  expressed  in  decimal  parts  of 
the  foot ;  for  example  :  5  inches  equal 
.42,  and  5i  equal  .43  ;  so  with  5i 
which  equal  .44  ;  in  like  manner  5'i 
equal    .45  ;     and    5i   correspond    with 


MARINE  AND  NAVAL  ARCHITECTURE. 


313 


.46  ;  thus  we  discover  that  the  deci- 
mal parts  of  the  foot  express  all  we 
require,  and  furnish  a  universal  system 
by  which  all  may  work  :  if  we  require 
the  sixteenth  of  an  inch  expressed  in 
decimals,  we  may  have  it  also  thus, 
005.  We  would  be  glad  if  this  system 
were  universal  in  the  ship-yard  as  well 
as  on  the  tables  of  displacement,  what 
an  almost  endless  number  of  mistakes 
might  be  avoided  !  One  man  expresses, 
for  example,  five  inches  and  three  quar- 
ters, 516  ;  another  will  set  it  down  51;  a 
third  5? ;  a  fourth  would  call  the  first 
example  5  feet  6  inches  ;  hence  it 
must  be  clear  to  the  thinking  man  that 
all  mechanics,  particularly  those  of  the 
same  business,  should  express  mea- 
surements in  the  same  manner.  What 
now  seems  perfectly  legible  to  one  man, 
is  hieroglyphics  to  another ;  and  we 
unhesitatingly  say,  that  every  mechanic 

should    fully   understand    the    decimal 
expressions  as  shown  on  page  3. 

It  may  not  be  necessary  to  carry 
our  expositions  farther,  believing  that 
they  will  be  readily  understood  by  the 
thinking  reader.  The  same  rules  ap- 
ply equally  well  to  any  part  of  the  ship, 
but  need  not  be  applied  on  the  outside. 
Indeed  they  cannot  be  applied  with  any 
considerable  advantage  until  the  bilge 
is  reached  from  below,  and  then  we  may 
not  find  it  advisable  to  be  confined  to 
equal  divisions  from  the  graded  scale. 


It  is  not  important  that  each  strake 
should  be  exactly  of  the  same  width 
below  the  wales  ;  indeed  it  adds  to  the 
symmetry  of  the  whole  structure  to 
have  the  strakes  freed  from  that  con- 
tinued sameness  that  is  consequent 
upon  having  a  great  many  strakes  of 
the  same  width.  The  strings  appear  to 
advantage  equally  divided,  as  also  do 
from  10  to  14  strakes  of  the  wales, 
(the  number  of  strakes  of  wales  is  va-« 
liable,  according  to  the  shape  and  size 
of  the  ship,)  but  below  these  the  di- 
minishing strakes  and  the  bottom  plank 
may  vary  in  width  to  advantage.  The 
true  principle  in  planking  and  ceiling 
may  be  shown  in  the  following  exposi- 
tion :  suppose  a  spot  is  made  at  the 
wood  ends,  both  forward  and  aft  the 
height  any  named  strake  is  required 
to  come,  a  spot  may  also  be  made  on 
one  of  the  midship  frames  at  which  the 
same  strake  is  required  to  come.  We 
will  now  assume  that  a  ram  line  be 
drawn  straight  from  the  wood  ends 
forward  to  the  same  aft,  and  made  fast 
at  each  spot ;  we  will  next  suppose  we 
can  take  a  range  that  wilt  bring  the 
line  and  the  spot  made  midship  in  the 
direction  of  each  other;  while  the  eye 
thus  cuts  the  spot  midship,  let  others 
be  made  at  convenient  distances  for 
lining  from  one  to  the  other,  both  for- 
ward and  aft;  and  having  the  line 
stricken  around  the  side  or  bottom,  we 


40 


314 


MARINE    AND    NAVAL    ARCHITECTURE. 


have  the  direction  the  strake  should 
run;  it  matters  not  whether  the  strake 
points  high  or  low  :  whether  the  strake 
be  on  the  bottom  or  on  the  side.  It 
may  be  thought  that  because  of  the 
cross  seam  preventing  the  rise  of  the 
after  end,  the  ride  would  be  useless; 
but  this  makes  no  difference  ;  the  strake 
comes  outboard  on  the  transom  in  the 
same  ratio  that  the  forward  end  rises. 
•  This  we  say  is  the  true  principle  upon 
which  the  direction  of  the  plank  both 
inside  and  outside  should  run.  If  the 
young  beginner  is  desirous  to  have 
this  mode  made  familiar  to  his  eye,  he 
may  apply  a  long  straight  edge  on  the 
upper  e<\ge  of  any  strake  he  may  select 
on  the  bottom  at  say  one-third  of  its 
length  from  forward  or  aft ;  let  the 
straight  edge  be  long,  and  for  conve- 
nience it  may  be  placed  with  its  upper 
edge  at  the  seam,  and  the  outer  end 
be  left  moveable,  in  order  that  it  may 
be  raised  or  lowered  until  the  eye  and 
the  edge  of  the  strake  blend  into  each 
other  ;  he  will  then  readily  discover  any 
discrepancy  in  the  direction — in  other 
words,  a  swell  or  a  hollow  will  be  readi- 
ly detected.  Before  moving  the  straight 
edge,  let  another  be  placed  one-third 
from  aft,  both  at  the  seam  and  out  of 
wind  with  the  first ;  the  sight  being  now 
taken  from  aft,  we  shall  see  how  the 
strake  forward  accords  with  the  prin- 
ciple laid  down.      We   repeat  that  it  is 


not  necessary  either  to  run  the  line  or 
to  apply  the  straight  edge.  We  have 
described  them  as  being  the  best  modes 
of  illustrating  the  subject.  With  re- 
gard to  the  ceiling,  it  does  not  follow 
that  the  strakes  would  run  as  they  do 
outside.  We  may  run  them  in  the  di- 
rection of  the  water-lines  if  we  please, 
with  the  ends  down  and  the  middle  up, 
and  still  the  principle  is  not  affected  ; 
or  we  may  keep  the  ends  higher  than 
those  on  the  outside.  We  may  readi- 
ly make  the  application  of  our  first  ex- 
position with  the  same  line  on  the  in- 
side, and  set  the  bilge  strake  in  this 
manner.  The  manner  of  arranging  the 
keelsons,  bilge  strakes,  and  ceiling,  is 
not  arbitrary.  Plate  21  exhibits  a 
very  efficient  mode  of  adding  strength 
to  a  ship  in  the  distribution  of  the  keel- 
sons, thick  strakes,  &.c.  It  may  now 
be  necessary  to  return  to  the  clamps, 
both  between  decks  and  in  the  lower 
hold.  We  assumed  that  it  was  only 
necessary  to  run  two  or  three  strakes 
before  putting  the  beams  across ;  we 
may,  at  a  suitable  time  after  the  deck 
is  laid,  run  the  remaining  strakes. 
There  may  be  some  objections  in  the 
minds  of  many  to  this  course,  inas- 
much as  the  tree-nails  in  the  wales 
being  driven,  must  of  necessity  be  cut 
off  and  wedged  on  the  timbers,  that 
the  tree-nails  should  go  through  the 
clamps.      To  obviate  this  the  tree-nails 


MARINE    AND    NAVAL    ARCHITECTURE. 


31o 


may  be  left  out  of  those  strakes,  par- 
ticularly opposite  the  lower  deck 
clamps  ;  it  is  quite  common,  however, 
to  commence  below,  or  at  the  bilge  to 
ceil,  and  follow  up  with  the  clamps. 
We  think  this  mode  objectionable,  in- 
asmuch as  it  keeps  the  lower  deck  be- 
hind, or  in  a  less  forward  state  of  ad- 
vancement than  the  upper  deck,  which 
should  not  be  the  case  under  ordinary 
circumstances. 

With  regard  to  the  strength  of  tree- 
nails,  there  can  be  no  question  of  their 
adding  a  great  amount  of  strength  to 
a  ship  ;  but  where  the  plank  is  heavy 
and  the  timbers  light,  we  prefer  bolts, 
particularly  on  the  inside  of  a  ship, 
where  the  corrosive  influence  of  rust  is 
less  than  on  the  outside.  We  say  that 
the  tree-nails  may  be  driven  harder 
through  the  wale  and  timber  than  if 
they  extended  through  the  clamp,  and 
being  wedged  on  the  timbers,  are  equal- 
ly as  good  as  if  they  extended  through  ; 
and,  as  a  consequence,  kept  a  bolt  out 
of  the  lower  deck  clamps,  where 
the  outside  plank  is  usually  thiner  than 
on  the  outside  of  those  above.  There 
should  be  system  in  fastening  ships, 
and  indeed  all  kinds  of  vessels,  and  we 
have  been  often  surprised  to  see  the 
loose  and  random  manner  in  which 
fastening  was  put  in  ships.  Not  a  bolt 
or  spike  should  be  driven  in  the  ceil- 
ing or  clamps  (where  the  tree-nails  are 


designed  to  come  through)  more  than 
is  actually  necessary  to  hold  the  plank 
to  the  timbers,  until  all  the  through 
fastening  is  in  from  the  outside  ;  and 
we  have  known  ships  that  were  thus 
systematically  fastened  to  be  set  down 
as  slightly  so,  because  the  fastening 
was  not  all  put  in  when  the  plank  was 
put  on. 

With  regard  to  the  amount  of  fast- 
ening  that  ships  require,  we  may  add, 
that  ships  having  two  or  more  decks 
require  40  pounds  of  iron  and  copper 
fastening  for  every  ton  of  displace- 
ment. This,  if  properly  distributed,  will 
square  fasten  the  ship  ;  that  is  to  say,  it 
will  allow  2  bolts  or  spikes  in  every  tim- 
ber where  there  are  no  tree-nails,  with 
an  abundance  for  frame  bolts,  thick 
strakes,  keelsons,  breast-hooks,  deck 
frames,  hanging  knees,  stanchions  ;  in 
a  word,  for  all  the  metal  fastening  re- 
quired in  a  ship. 

We  deem  it  qufte  unnecessary  to 
protract  our  remarks  on  the  manner 
of  construction  in  the  present  chap- 
ter, nor  would  we  underrate  the  ability 
of  those  who  may  feel  themselves 
qualified  to  build  a  ship.  The  expo- 
sition of  some  important  rules  that  have 
been  illustrated  but  not  explained,  may 
suffice  for  this  chapter. 

The  first  we  shall  notice  is  found  on 
Plate  8,  Fig.  1.  This  represents  one 
of  the  readiest  modes  of  obtaining  the 


316 


MARINE    AND    NAVAL    ARCHITECTURE. 


sweep  of  a  beam-mould  or  arch-board. 
It  will  be  discovered,  that  like  all  other 
sweeps  it  has  a  base-line  ;  this  line  is 
straight,  and  extends  the  entire  length 
the  mould  is  required  to  be.  The  cen- 
tre of  this  length  is  obtained,  at  which 
point  a  perpendicular  is  raised,  and  the 
required  round  set  up,  a  quarter  circle 
being  swept  from  the  perpendicular  to 
the  base,  is  divided  into  any  convenient 
number  of  parts.  The  diagram  shows 
5  equal  parts  each  side  of  the  centre. 
As  will  be  seen,  the  quarter  circle  is 
also  divided  into  5  equal  parts,  both 
on  the  base  and  on  the  circle,  and  lines 
drawn  from  one  to  the  other;  the  an- 
gle is  then  taken  with  a  protrac- 
tor or  bevel  in  the  direction  of  the 
division  and  at  the  corresponding  lines 
on  the  base,  that  will  bring  their  in- 
clination from  the  centre  of  the  base,  as 
shown  in  the  dotted  lines ;  the  sev- 
eral heights  of  the  dotted  lines  in  the 
quarter  circle  may  next  be  taken,  and 
applied  on  those  inclined  lines,  and  a 
batten  bent  to  the  spots;  while  the 
batten  is  thus  bent,  we  may  divide  the 
curve  shown  by  its  edge  into  equal 
parts  ;  we  then  remove  the  bat- 
ten without  marking  it,  and  draw  lines 
from  the  divisions  on  the  base  to  the 
last  divided  spots, and  set  up  the  heights 
on  those  lines;  again  bend  the  batten 
to  the  last  spots,  and  mark  by  the  bat- 
ten the  curve,  which  is  the  true  curva- 


ture of  a  circle.  It  will  be  perceived, 
that  inasmuch  as  the  quarter  circle  is 
divided  into  equal  parts,  it  is  necessary 
to  divide  the  large  circle  in  the  same 
manner  ;  and  that  the  segment  of  the 
large  circle  cannot  be  divided  before  it 
is  made;  and  for  the  purpose  of  ob- 
taining an  approximation,  we  have 
shown  the  angles  ;  a  square  line,  how- 
ever, would  doubtless  answer  the  same 
purpose.  Fig.  2  shows  another  mode 
of  obtaining  the  same,  but  is  better 
adapted  to  sweeps  that  have  more 
round  in  an  equal  length  than  Fig.  1. 
For  example:  to  an  arched  hog  frame 
on  a  steamboat,  Fig.  2  would  be  bet- 
ter adapted  for  showing  its  periphery 
than  Fig.  1  ;  it  is  quite  simple,  and  is 
made,  as  will  be  seen,  by  first  striking 
a  base,  then  raising  a  perpendicular, 
and  setting  up  the  height  of  the  re- 
quired arch  ;  this  height  divided  into 
any  number  of  parts,  a  sufficient  num- 
ber to  sweep  by  is  all  that  is  required ; 
from  the  upper  spot  strike  a  line  to 
the  terminus,  from  which  we  raise 
another  perpendicular,  and  again  di- 
vide as  before.  Lines  stricken  to  all 
those  settings-off,  and  repeated  on  the 
opposite  side,  will  furnish  intersections 
on  their  corresponding  lines,  as  shown 
in  Fig.  2,  and  arc  the  spots  required 
for  the  circumference  of  the  circle. 
We  have  also  shown,  on  Plate  11, 
another  mode   of  obtaining  the   same 


MARINE    AND    NAVAL    ARCHITECTURE. 


317 


curve,  usually  used  for  beam  moulds ; 
it  is  formed  by  the  base  perpendicular 
and  equal  division  principle  ;  it  is  sim- 
ple in  its  construction,  and  requires, 
we  think,  only  to  be  attentively  ex- 
amined, as  shown  by  the  diagram,  to 
be  readily  understood.  Fig.  1,  Plate 
18,  is  designed  to  describe  the  arc  of 
a  circle  that  shall  contain  anv  number 
of  degrees  ;  the  operation  being  per- 
formed without  compasses,  and  in  one 
particular  like  the  former  examples, 
without  finding  the  centre  of  the  cir- 
cle :  place  two  rulers  forming  an  angle, 
as  shown  in  the  diagram  ;  let  the  angle 
be  equal  to  the  supplement  of  half  the 
given  number  of  degrees.  (The  sup- 
plement of  an  arc  or  angle  is  what 
must  be  added  to  it  in  order  to  make 
a  semicircle  or  ISO  degrees,)  and  fix 
them  as  shown,  their  connection  above 
being  the  altitude  we  require,  or  their 
upper  edges  forming  the  angle  we  de- 
sire with  the  base.  Place  two  pins  at 
the  extremities  of  the  given  chord  at 
the  termination  of  the  sweep,  and  hold 
a  pencil  in  the  socket  formed  by  the 
union  of  the  rulers  above,  or  on  their 
upper  edge :  then  move  the  edges  of 
this  instrument  against  the  pins,  and 
the  pencil  will  describe  the  arch  re- 
quired. Suppose  it  is  required  to  de- 
scribe an  arch  of  50  degrees  on  a  chord 
of  given  length,  or  on  a  base  of  given 
length,   (the   chord  is  the  straight  line 


which  joins  the  two  extremities  of  the 
arc  of  a  curve,  so  called  from  the  re- 
semblance which  the  arc  and  the  chord 
together  have  to  a  bow  and  its  string, 
the  chord  representing  the  string;)  sub- 
tract 25  degrees  (which  is  half  the 
given  angle)  from  180,  and  the  differ- 
ence, 155  degrees,  will  be  the  supple- 
ment ;  then  form  an  angle  of  155 
degrees  with  two  rulers,  and  proceed  as 
shown  in  the  diagram.  Fig.  2,  Plate 
18,  shows  the  proportionate  taper  of 
spars.  We  have  assumed  that  either 
of  the  straight  boundary  lines  were 
the  base,  and  have  dropped  the  per- 
pendiculars from  the  circle  to  both 
lines,  showing  that  the  results  are  the 
same.  This  sweep,  used  by  spar- 
makers,  (when  there  were  fewer  spars 
made  than  at  the  present  time,)  fur- 
nished the  proportionate  taper  of  all 
sized  spars.  But  the  practice  of  draw- 
ing a  sweep  for  a  spar  of  any  descrip- 
tion, has  long  since  grown  obsolete  ; 
it  is  only  necessary  to  know  the  length 
and  diameter,  and  the  spar-maker  will 
at  once  mark  with  a  piece  of  chalk 
these  same  proportions  on  his  rule 
within  the  half  diameter  of  the  spar  in 
its  largest  place.  Suppose  the  spar  to 
be  made  be  a  yard  75  feet  long  and  18 
inches  in  the  slings,  or  4  feet  of  length 
for  every  inch  of  diameter,  which 
is  recognized  as  the  proportion  for 
smaller  spars  in  the  mercantile  marine, 


318 


MARINE    AND    NAVAL    ARCHITECTURE. 


1*>!  would  be  the  proper  diameter  for 
this  yard  ;  'but  this  is  about  as  near  as 
spar- makers  generally  come  to  any 
standard  of  proportions.  Another  ex- 
ample may  serve  to  show  how  near 
proportions  are  carried  out  in  spar- 
making:  the  ends  of  lower  yards  are 
set  down  at  half  an  inch  less  than  half 
the  size  of  the  slings,  but  it  is  quite 
common  to  find  them  botli  above  and 
below  this  medium.  We  have  long 
since  come  to  this  conclusion  from 
close  observation,  that  proportions  for 
yards  were  far  from  being  good. 
Doubtless  the  experience  of  a  long  life 
of  sea-service  would  scarcely  witness 
the  carrying  away  of  a  yard  in  any 
other  part  than  the  slings ;  this,  it 
seems  to  us,  should  teach  the  think- 
ing man  that  they  are  too  small  in  the 
slings.  The  manifest  error  in  the 
same  rule  when  applied  to  lower  masts, 
becomes  apparent,  even  to  the  casual 
observer.  A  lower  mast,  of  85  feet, 
would  be  made  not  less  than  32  inches 
in  the  partners,  which  would  differ  but 
little  from  one  inch  of  diameter  for 
every  2s  feet  of  length.  There  never 
has  been  any  system  brought  forward 
that  would  universally  apply  to  all  de- 
scriptions of  spars  ;  we  cannot,  how- 
ever, suppose  that  the  proportions  now 
used  for  lower,  top-sail,  and  top-gallant 
yards,  are  free  from  manifest  discre- 
pancies.     To  illustrate  tin-  proportions 


now  in  use,  and  in  order  that  we  may 
be  clearly  and  fully  understood,  we  will 
add,  that  it  is  not  our  purpose  to  fur- 
nish in  this  chapter  any  proportions 
for  spars  as  connected  with  the  vessels 
for  which  they  are  intended,  but  to 
analyze  the  manner  of  proportioning 
the  one  part  of  a  spar  to  the  other 
after  the  dimensions  are  given ;  in  a 
word,  we  have  at  present  nothing  to 
say  to  the  builder  who  furnishes  the 
dimensions  of  the  spars,  but  to  the 
spar-maker  who  makes  them  ;  (they, 
however,  are  often  confined  to  glaring 
errors  and  manifest  discrepancies  by 
the  masters  of  vessels,  who  suppose 
they  know  about  all.)  We  will  com- 
pare the  proportions  given  at  the  sev- 
eral settings-off  of  a  yard  with  those 
we  shall  propose,  and  draw  such  in- 
ferences as  the  subject  may  demand. 
Assuming  a  lower  yard  to  be  80  feet 
long,  and  20  inches  in  the  slings,  strike 
a  centre  line  on  the  spar,  (after  spot- 
ting it  to  prevent  its  rolling,)  middle  it, 
and  divide  each  half  length  into  4 
equal  parts,  which,  with  the  middle  and 
end,  will  make  5  spots  or  settings-off. 
The  ordinary  settings-off  or  sizes  to  be 
applied  at  the  several  spots  each  side 
of  the  centreline  would  be  as  follows: 
in  the  centre  10  inches  ;  at  the  first  set- 
ting-off from  the  centre  on  each  end. 
91 ;  at  the  second  setting-off  or  spot, 
St  inches  ;  at  the  third,  7  inches  ;   and 


Sii 


MARINE    AND    NAVAL    ARCHITECTURE. 


,VA 

at  the  fourth  spot  or  end,  41  inches. 
Thus  we  discover  that  in  the  slings 
the  yard  is  20  inches;  at  the  first  set- 
ting-off 191  inches ;  at  the  second, 
17£  inches  ;  at  the  third,  14  inches  ; 
and  at  the  end,  9i  inches.  We  have 
shown  another  kind  of  sweep  in  Fig-. 
3,  that  will  furnish  better  proportions 
than  that  of  Fig.  2 :  by  applying  the 
settings-off  as  taken  from  the  diagrams 
to  the  scale  of  three-quarters  of  an 
inch,  we  shall  discover  the  variations 
in  the  size  of  the  same  yard,  of  the 
same  size  in  the  slings,  and  an  equal 
number  of  settings-off.  The  first  set- 
ting-off from  the  sling  furnishes  the 
same  as  the  first,  19£  inches ;  the  sec- 
ond, 16?  inches  ;  the  third,  12  inches  ; 
and  the  end,  6f  inches.  Now,  we  hesi- 
tate not  to  say.  that  spar-makers  them- 
selves will  acknowledge  that  a  yard 
made  by  those  dimensions  would  be  as 
likely  to  break  any  where  else  as  in 
the  slings,  and  not  any  more  ;  of  course 
there  should  be  an  allowance  in  size 
for  the  weakening  tendency  of  the 
sheave-hole,  and  beyond  this  nothing 
more  would  be  required.  Fig.  4, 
Plate  18,  is  designed  to  illustrate  the 
division  of  the  circle  into  degrees  or 
angles ;  the  quarter  of  the  circle  con- 
taining 90  degrees  and  forming  the 
square,  and  one-eighth  containing  45 
degrees,  which  is  the  mitre  or  the  right 
angle   equally    divided,  and   is   usually 


319 


recognized  in  the  ship-yard  as,  and 
taken  with,  the  be.vel.  It  does  not, 
however,  necessarily  follow,  that  the 
mitre  can  be  obtained  only  in  the  angle 
of  45  degrees ;  the  equal  division  of 
any  angle  into  two  parts  constitutes 
the  mitre  of  that  angle  ;  45  degrees  is 
the  mitre  of  a  square  ;  90  degrees,  or 
the  square,  is  the  mitre  of  the  semi- 
circle, or  of  ISO  degrees.  It  makes  no 
difference  how  large  or  how  small  the 
circle  may  be  that  is  to  be  divided  into 
degrees.  The  circle  of  our  earth  con- 
tains no  more  degrees  than  that  of  an 
orange,  and  the  angles  are  the  same  ; 
hence  we  say,  that  the  only  correct 
mode  of  taking  the  dead  rise  of  vessels, 
or  of  their  sharpness,  is  by  taking  the 
angle  in  degrees,  or  by  taking  the  frac- 
tional parts  of  a  foot  of  rise,  &c,  con- 
tained in  a  foot,  which  is  the  same 
thing  ;  it  applies  to  the  rake  of  masts, 
the  descent  a  vessel  has  on  the  stocks, 
and  of  the  ways  for  launching  ;  and  we 
confidently  believe  that  were  angular 
measurements  adopted  more  generally 
in  the  ship-yard,  much  might  be  gained 
by  way  of  correcting  errors  and  of  fa- 
cilitating work. 

Although  much  has  been  said  by 
mathematicians  in  all  ages  about  the 
circle,  and  the  determination  of  the 
ratio  of  the  circumference  to  the  di- 
ameter, yet  it  still  remains  a  problem 
for  solution,  and  the  circle,  in  connec- 


320 


MARINE    AND    NAVAL    ARCHITECTURE 


trun  with  the  straight  line,  are  the  only 
two  figures  admitted  into  plane  or  ele- 
mentary geometry  ;  and  , the  question 
may  have  bce.ii  often  asked,  what  has 
geometry  to  do  with  the  practical  op- 
erations of  a  ship-yard?  We  answer, 
much  more  than  is  generally  supposed. 
Did  the  operative  mechanic  mingle  the 
elementary  principles  of  geometry  with 
his  daily  practice,  he  would  he  enabled 
to  cut  closer  or  with  more  certainty  of 
success.  Why  is  it  that  the  butt  of  a 
plank  on  the  luff  of  a  vessel's  bow  is 
cut  too  short  or  too  long?  or  why  does 
the  blacksmith  make  a  band  or  the 
grummet  of  a  yard  too  large  or  too 
small  ?  It  is  because  he  has  never 
studied  the  properties  of  the  circle ;  if 
he  had,  he  would  have  learned  that  his 
bar  of  iron  should  be  three  times  its 
thickness  longer  than  the  circumference 
of  the  spar,  rudder,  or  whatever  is  to 
be  banded,  in  addition  to  the  weld,  inas- 
much as  the  circle  is  three  times  the 


diameter,  (or  differs  but  a  trifle  from 
that  proportion.)  The  usual  mode  of 
determining  the  circumference  from 
the  diameter  is  as  follows,  (and  is  near 
enough  for  ordinary  purposes  :)  multi- 
ply the  diameter  by  22,  and  divide  the 
product  by  7,  the  quotient  will  be  the 
circumference  very  nearly.  But  again, 
the  cone  has  a  prominent  claim  on  the 
attention  of  practical  men  in  the  con- 
struction of  ships,  as  well  as  other 
branches  of  mathematics.  The  opera- 
tive mechanic  would  be  awed  into 
wonder,  at  the  astounding  intelligence 
that  the  sni  of  a  plank  may  be  deter- 
mined with  far  greater  accuracy  by 
the  aid  of  conic  sections  than  with  a 
rule  staff;  the  blacksmith  may  also  be 
better  enabled  to  band  a  bow-sprit  cap 
with  a  knowledge  of  the  properties  of 
the  cone,  and  yet  the  circle  and  the 
straight  line  furnish  all  the  figures  that 
are  necessary  to  its  practical  applica- 
tion. 


v  t !    fe    *  - 


■■  •+    ■ 


: 


CH* 


*~. 


«B.     » 


* 


MARINE  AND  NAVAL  ARCHITECTURE. 


321 


CHAPTER    X. 


Steamboats — Ocean  Steamers — Coasting  Vessels — Vessels  Suited  to  River  Navigation. 


With  feelings  of  pride  and  patriotism 
we  launch  into  the  subject  forming 
the  van  of  the  present  chapter.  As' 
the  discovery  of  the  art  of  printing  has 
partially  and  must  finally  dispel  the 
gloom  of  barbarism,  so  the  discovery 
and  application  of  steam  to  navigation 
and  the  purposes  of  commerce,  tend  to 
elevate  the  physical  and  moral  condi- 
tion of  mankind.  In  connection  with 
the  history  of  steam  navigation,  the 
name  of  no  individual  stands  more 
prominent  than  that  of  Robert  Fulton, 
a  man  of  whose  genius,  indomitable 
perseverance,  and  unbending  ener- 
gy, Americans  may  well  be  proud. 
Whether  we  witness  in  our  imagina- 
tion his  experiments  in  submarine  and 
torpedo  warfare  in  France,  in  1801,  or 
on  the  17th  of  August,  1807,  form 
one  of  the  incredulous  company  that 
thronged  the  wharves  of  this  city  to 
witness  his  first  effort  to  navigate  the 
Hudson  by  steam  at  the  then  surpass- 
ing speed  of  5  miles  per  hour,  we  must 
regard  him  as  a  man  possessing  me- 
chanical powers  of  mind  of  an  extra- 


ordinary calibre  ;  inasmuch  as  his  first 
steamboat  was  crude  both  in  dimen- 
sions and  form,  lacking  that  essential 
qualification,  stability,  and  was  subse- 
quently widened,  in  order  to  afford  the 
necessary  amount. 

It  may  not  be  out  of  place  to  fur- 
nish a  brief  description  of  Mr.  Fulton's 
first  effort  at  steamboat  building,  more 
particularly  when  we  are  assured  that 
no  mechanical  drawing  of  the  hull  was 
ever  made.  The  boat  was  133  feet 
long,  18  feet  wide,  and  7  feet  deep,  and 
was  subsequently  made  22  feet  wide, 
by  adding  a  strip  of  4  feet  to  her  mid- 
dle, which  also  increased  her  length  to 
141  feet.  Her  bottom  was  formed  of 
yellow  pine  plank  of  1*  inches  thick, 
tongued  and  grooved,  and  set  together 
with  white  lead.  This  bottom  or  plat- 
form was  laid  on  a  transverse  platform, 
and  moulded  out  with  batten  and  nails. 
The  shape  of  the  bottom  being  thus  for- 
ward, the  floors  of  oak  and  spruce  were 
placed  across  the  bottom  ;  the  spruce 
floors  being  4x8  inches,  and  2  feet 
apart  ;  the   oak   floors  being  reserved 


41 


322 


MARINE    AND    NAVAL    ARCHITECTURE 


for  the  engine,  and  the  spruce  for  the 
ends ;  the  oak  floors  both  sided  and 
moulded  8  inches.  Her  top-timbers 
(which  were  of  spruce,  and  extended 
from  a  log  that  formed  the  bilge  to  the 
deck)  were  sided  6  inches  and  mould- 
ed 8  at  heel,  and  both  sided  and 
moulded  4  inches  at  the  head.  She 
had  no  guards  when  first  built,  and 
was  steered  by  a  wheel  in  a  cockpit.. 
Her  draught  of  water  was  28  inches. 
She  had  1  boiler  20  feet  long,  7  feet 
deep,  and  8  feet  wide  ;  her  cylinder 
was  24  inches  in  diameter,  with  4  feet 
stroke  ;  her  wheel  was  15  feet  in  di- 
ameter, with  8  arms  ;  the  buckets  or 
paddles  had  30  inches  face,  and  2  feet 
dip ;  her  shaft  was  of  cast  iron,  4J 
inches  in  diameter,  under  the  deck,  and 
had  a  fly-wheel  of  10  feet  diameter  out- 
side of  the  boat ;  the  arms  of  the  wheel 
extended  below  the  bottom,  and  were 
the  source  of  great  inconvenience  in 
shoal  water.  She  was  called  first  the 
North  River,  and  subsequently  the 
Clermont,  in  honor  of  Chancellor  Liv- 
ingston, who  resided  at  Clermont,  on 
the  Hudson,  about  40  miles  below  Al- 
bany. As  no  complete  draft  of  the 
hull  of  this  boat  (either  before  or  after 
she  was  widened)  has  ever  been  shown, 
the  world  cannot  contrast  all  the  im- 
provements of  nearly  half  a  century  ; 
but  we  shall  show  our  readers  the  sec- 
ond boat,  designed  and  drawn  by  Mr. 


Fulton's  own  hand  in  1808.  Plate  22 
furnishes  an  exact  copy  taken  from 
the  original  drawing  of  the  steamboat 
Raritan, built  to  run  on  the  Raritan  riv- 
er. In  shape  she  differs  but  little  from 
the  Clermont,  and  with  the  exception 
of  an  amendment  in  dimensions, and  the 
addition  of  guards,  she  is  a  fair  repre- 
sentation of  the  first  steamboat  that 
plied  the  waters  of  the  Hudson.  We 
shall  give  Mr.  Fulton's  instructions  for 
building  this  boat,  as  appended  to  the 
draft,  and  directed  to  Mr.  Livingston, 
in  his  own  words  : — 

"  As  you  will  have  more  and  greater 
waves  than  the  North  river  boat,  the 
wheel  guards  must  be  so  constructed 
that  the  head  of  the  wave  shall  not 
strike  under  them.  I  would  finish 
them  as  here  delineated :  they  are  4 
feet  from  the  water  ;  A  A,  keelsons  for 
the  boiler,  8  feet  6  inches  from  outside 
to  outside  ;  B  B,  keelsons  for  the  ma- 
chinery, 7  feet  from  outside  to  outside  ; 
C,  hatchway  to  let  in  the  boilers,  8 
feet  4  wide,  21  feet  long.  See  Figure 
the  1st.         ROBERT  FULTON. 

"  October  22d,  1808. 
"  John  R.  Livingston,  Esq." 

We  cannot  but  look  upon  the  first 
efforts  of  Mr.  Fulton  at  steamboat 
building  with  admiration  ;  possessing  a 
mind  in  every  respect  adequate  to  the 
gigantic  enterprise  that  lay  before  him  ; 


MARINE    AND    NAVAL    ARCHITECTURE. 


323 


wasting  health  and  life  in  midnight 
thought  and  painful  study;  dreaming 
of  science  in  the  broken  slumbers  of 
an  exhausted  mind,  he  steadily  pressed 
on  toward  the  goal  of  all  his  hopes, 
and  in  the  year  1816  had  constructed 
and  supervised  the  building  of  15  steam 
vessels  during  a  period  of  10  years, 
the  longest  of  which  was  175  feet. 

It  wan  Id  have  required  a  vision  of 
more  than  ordinary  strength  to  have 
looked  through  the  vista  of  time  for  a 
distance  commensurate  with  less  than 
half  a  century  to  a  period  when  the 
speed  of  steamboats  upon  the  same 
river  on  which  Fulton  harnessed  his 
trackless  steed,  should  have  increased 
from  5  to  20  miles  per  hour,  and  when 
the  motive  power  (versus  pressure  on 
the  boiler)  should  be  increased  from 
that  of  8  to  50  pounds  per  square 
inch  ;  we  say  that  the  mind  capable 
of  grasping  and  keeping  pace  with  such 
wondrous  results,  in  so  short  a  time, 
must  be  expansive  indeed  ;  but  when 
we  remember  that  not  only  this,  but 
far  greater  achievements  belong  to 
America  in  steam  navigation,  the  com- 
mercial world  instinctively  bows  to  the 
fecundity  of  American  genius,  while 
her  ocean  steamers  are  ploughing 
trackless  furrows  in  every  sea,  and 
leaving  their  tardy  rivals  far  in  their 
wake.  Such  has  been  the  progress  of 
steam,  that  the  domain  of  old  Neptune 


has  been  invaded,  and  as  if  regardless 
of  his  regal  wrath  expanded  in  foam- 
ing billows,  or  the  caresses  of  his 
boundless  mirror. 

The  construction  of  steamboats  has 
engaged  some  of  the  loftiest  concep- 
tions of  the*  age,  and  our  steam  river 
navigation  still  forms  a  great  theatre 
of  nature,  inviting  us  to  those  bold 
researches  in  which  science  engages 
with  such  keen  delight. 

In  our  expositions  on  the  laws  of 
resistance,  we  took  occasion  to  make 
some  deductive  remarks  on  steamboats, 
which  may  be  found  on  page  66,  and 
onward.  In  building  steamboats,  the 
first  and  most  important  consideration 
is  proper  dimensions,  without  which 
our  hopes  for  superiority  will  be  futile. 
There  is  no  analogy  existing  between 
the  proportions  of  length,  breadth  or 
depth  of  steamboats,  as  compared  with 
sailing  vessels,  (we  allude  to  river  boats 
as  now  constructed  on  the  Hudson 
and  other  rivers.)  The  reason  is  ob- 
vious to  the  thinking-man — they  are 
required  for  great  speed,  which  is  only 
attainable  by  having  great  length  and 
a  sufficiency  of  breadth  to  secure  the 
stability  of  equilibrium,  and  no  more 
depth  than  the  grand  object  at  which 
we  aim  (viz.,  speed)  requires.  The 
reasons  will,  we  think,  appear  obvi- 
ous: first,  great  length  pie-supposes 
acute  lines  ;   or,  in  other   words,  two 


324 


MARINE    AND    NAVAL    ARCHITECTURE. 


ends,  and  but  little  middle  longitudi- 
nally ;  that  is  to  say,  an  additional 
breadth  is  added  to  the  sides  of  the 
model  for  the  purpose  of  making  it 
sharper ;  hence  it  follows,  that  if  the 
additional  length  were  added  to  the 
ends  for  the  purpose  of  sharpening 
them,  no  addition  can  be  made  to  the 
middle  in  length  that  will  accomplish 
the  same  object.  We  mean  by  this,  that 
great  speed  cannot  be  gained  by  in- 
creasing the  length  midships,  and  re- 
taining the  same  or  nearly  the  same 
shaped  ends  as  before  ;  this,  however, 
is  often  done  to  secure  alight  draught 
of  water,  but  always  at  the  expense  of 
speed ;  true,  we  may  gain  an  equal 
amount  of  stability  with  less  breadth  in 
the  boat  having  short  ends  and  a  long 
middle,  and  in  addition  to  this  the  boat 
is  made  to  show  a  smaller  registered 
tonnage.  But  look  at  the  consequences; 
the  boat  is  shorn  of  her  speed  from  1 
to  5  miles  per  hour,  and  at  once  set 
down  as  a  second  class  boat,  when  she 
might,  with  the  same  cost,  have  been 
rated  a  first. 

Steamboats  in  this  age  of  the  world 
are  rated  by  their  speed,  or  in  accord- 
ance with  the  degree  of  speed  attained  ; 
and  we  think  we  hazard  nothing  in 
stating  it  to  be  our  firm  conviction, 
that  steamboats  may  be  built  that  would 
be  able  to  make  the  run  to  Albany 
w  ithin  6  hours,  at  no  greater  cost  than 


some  other  boats  that  could  scarce 
make  the  run  within  8  hour?  This 
enterprise  can  only  be  accor  yplished 
by  allowing  the  builder  to  have  discre- 
tionary power  in  dimensions,  shape, 
and  the  weight  of  the  boat ;  and  the 
engineer  to  proportion  the  engine  and 
boilers  in  accordance  with  his  superior 
judgment ;  and  the  captain  to  have 
nothing  to  say  farther  than  to  judge 
of  the  quality  of  the  materials 'and  of 
the  work.  We  are  persuaded  that  it 
would  be  much  more  difficult  to  secure 
such  an  arrangement,  than  to  accom- 
plish the  work  of  building  the  boat  to 
perform  the  trip  in  the  given  time  ; 
consequently  we  must  allow  those  pas- 
sengers whose  business  compels  them 
to  travel  in  haste,  to  take  the  railroad, 
until  captains  and  owners  shall  have 
learned,  that  that  which  they  cannot 
do,  can  be  done  by  mechanics. 

A  light  draught  of  water  seems  to 
be  the  grand  desideratum  with  the 
greatest  portion  of  steamboat  men  ; 
but  unless  it  is  obtained  at  the  expense 
of  weight,  or  by  other  means  than  those 
generally  adopted,  it  is  only  secured  at 
the  expense  of  speed.  It  would  be 
hazardous  to  attempt  to  furnish  any 
standard  of  proportionate  dimensions 
for  steamboats  ;  the  circumstances  are 
so  variable  under  which  steamboats 
are  built,  that  what  would  be  a  jusl 
proportion   in   one  case,  would  be  far 


MARINE    AND    NAVAL    ARCHITECTURE. 


325 


from  the  same  in  another.  The  engine 
and  boilers  are  so  variable  in  the  altitude 
of  their  centre  of  gravity,  that  the  di- 
mensions and  the  power  should  be 
taken  in  connection  ;  under  ordinary 
circumstances  from  9  to  10  feet  of 
length  to  1  of  breadth,  and  3  of  breadth 
for  1  of  depth,  are  deemed  just  propor- 
tions for  river  boats  with  beam  engines. 
Many  persons  have  supposed,  that  if 
the  relations  between  the  breadth  and 
depth  remained  the  same,  that  the 
length  might  be  increased  to  advan- 
tage for  speed.  This  is  not  strictly 
true  ;  the  stability  is  sensibly  affected 
when  this  is  the  case ;  but  it  does  not 
follow  that  the  breadth  should  be  in- 
creased on  all  parts  of  the  greatest 
transverse  section  in  the  same  ratio  ; 
our  object  may  be  gained  by  increas- 
ing the  breadth  at  the  load-line  of  flo- 
tation,  while  at  the  middle  of  the  bilge 
it  remained  as  before.  We  have  al- 
ready remarked,  that  an  easy  bilge  was 
an  essential  qualification  for  high 
speed,  and  that  a  large  column  of  water 
should  pass  between  the  wheel  and  the 
bilge.  This  answers  a  two-fold  purpose: 
it  cuts  down  the  resistance.,  and  at  the 
same  time  sustains  the  boat  where 
buoyancy  is  most  required ;  and  while 
it  is  absolutely  necessary  that  the  boat 
should  be  entirely  flat,  that  is  to  say, 
that  she  should  have  little  or  no  dead- 
rise  ;  it  is  also  still  more  essential  that 


she  should  present  but  little  really  flat 
surface  to  the  fluid.  Abundant  proof 
of  this  is  afforded  almost  every  day  of 
the  travelling  season  on  the  Hudson — 
a  river  doubtless  unsurpassed  for  its 
natural  facilities  afforded  for  experi- 
menting on  a  wide  and  extensive  scale 
on  steamboats — being  at  some  parts 
wide  and  deep,  while  at  others  it  is 
narrow  and  shoal  ;  and  again,  in  other 
places  narrow  and  deep,  while  at 
another  we  find  it  wide  and  shoal. 
Thus  the  observing  mechanic  may 
readily  determine  the  best  shape  for 
speed,  even  though  he  be  unskilfully 
versed  in  the  philosophy  of  nature's 
laws.  The  boat,  with  an  extensive  flat 
or  straight  surface  on  the  bottom  when 
in  shoal  water,  will  generate  a  much 
larger  wave  on  each  quarter  than  the 
boat  having  less,  and  will  actually 
ground  when  another  will  pass  over, 
that  would  actually  draw  more  water 
when  at  rest ;  the  same  results  are 
consequent  upon  the  straight  side  lon- 
gitudinally when  the  boat  is  near  the 
shore.  Few  indeed  there  are  who  can 
form  a  just  conception  of  the  effect 
upon  the  speed  of  a  steamboat  when 
in  shoal  water,  or  in  a  narrow  pass  of 
the  river. 

With  regard  to  the  proper  shape  for 
speed,  we  will  say,  that  the  greatest 
transverse  section  or  <3>  frame  is  found 
to  be  well  adjusted  when  in  the  centre 


026 


MARINE    AND    NAVAL    ARCHITECTURE. 


of  length,  and  the  buoyancy  equally 
distributed  each  side  of  the  longitudi- 
nal centre  of  length.  The  centre  of 
effort  should  be  higher  than  in  sailing 
vessels,  to  counteract  the  leverage  of 
the  engine,  or  its  centre  of  gravity  over 
that  of  the  centre  of  displacement,  it 
being  usually  above  the  deck  of  the 
boat.  Although  the  displacement  on 
the  two  ends  of  the  boat  should  be 
about  equal,  it  does  not  follow  that 
they  should  be  of  the  same  form,  either 
at  the  line  of  flotation  or  on  any  part 
below  that  line ;  the  sharpest  end  of 
the  boat  should  go  foremost,  and  yet  it 
must  be  observed,  the  after  end  cannot 
be  a  great  deal  fuller  than  the  fore 
end,  or  the  centre  of  buoyancy  would 
not  be  at  the  centre  of  length  ;  this  is 
accomplished  by  making  the  lines  on 
the  bow  hollow  longitudinally ;  this 
form  of  line  makes  the  least  disturb- 
ance, and  if  sufficiently  acute,  will  not 
translate  the  fluid  into  foam  by  throw- 
ing it  off  from  the  bow  ;  we  may  rest 
assured,  that  there  is  an  unnecessary 
amount  of  resistance  where  the  fluid 
is  either  thrown  off  or  the  smallest 
wave  generated.  A  given  amount  of 
fullness  may  be  forced  through  the 
water  with  less  disturbance,  by  entering 
with  an  acute  line  and  gradually  in- 
creasing the  angle  of  resistance  as  we 
advance  ;  whereas,  had  we  commenced 
with  the  same  angle   that  we  present 


two-thirds    of  the   distance    from    the 
stem  to  the  0,  we  should  have  lifted  a 
sheet  of  water  close  to  the  stem,  which 
would   again   meet   us  with    redoubled 
force,  and  must  again  be  thrown  off  in 
consequence  of  the  accelerated  force 
with  which  it  moves.     It  should  be  re- 
membered   that    this    sheet    of   water 
raised  on  the  bow  generates  a  wave, 
(and  that  wave,  unlike  one  generated 
by  the  friction  of  the  wind,  that  merely 
oscillates  and  has  no  progressive    mo- 
tion ;)  this  wave  meets  the  bow  again 
farther  aft,   but    the    resistance    is   in 
creased  by   the   accelerated  motion   oy 
the   wave,   which    is    thrown    off  ana1 
again   returned   with  increased  force 
thus  a  succession  of  concussions  talc 
place,  that  diminishes  the  speed  to   ■ 
very  great  extent.     It  requires  but  ? 
glance  at  the  inevitable  results,  to  ena- 
ble   us  to  imagine  the  amount  of  r« 
sistance  on  the  bow  of  a  steamboal, 
when   we  remember  that  the  vertical 
pressure  on  each  square  foot  of  surface 
of  fluid  equals  2,160  pounds,  and  tlu>l 
there  must  be  an  excess  of  pressure 
on  the  bow   before  the   wave   can    be 
formed.      The  pressure  on  the  bow  and 
stern  must  be  equal  to  the  whole  pow- 
er of  the  engine  ;   and  as  the  speed  of 
the  boat  is  increased,  the  wheel  makes 
more   revolutions  with  the  same  pres- 
sure of  steam.     The  number  of  revolu- 
tions of  the  wheel  in  a  given  time,  niul- 


MARINE    AND    NAVAL    ARCHITECTURE. 


327 


liplied  by  the  periphery  of  the  wheel 
taken  at  the  centre  of  the  bucket  or 
paddle,  furnishes  data  for  determining 
the  relative  speed  of  a  boat  ;  but  there 
is  a  certain  allowance  to  be  made  for 
what  is  usually  termed  the  slip  of  the 
wheel,  which  is  the  yielding  property 
of  the  water  ;  this  amount  is  usually 
set  down  at  20  per  cent.,  but  is  varia- 
ble, consequent  upon  the  amount  of 
dip  to  the  bucket,  the  number  of  arms 
in  the  wheel,  &c. 

It  must  be  quite  apparent  that  a 
steamboat  cannot  turn  her  wheel 
around  as  often  in  a  given  time  when 
made  fast  at  the  wharf,  as  when  in 
motion  or  under  way,  though  the  same 
amount  of  power  be  exerted  ;  the 
same  may  be  said  with  equal  propriety 
of  a  boat  that  has  more  resistance  than 
another  with  the  same  sized  wheel  and 
power.  The  problem  is  a  plain  one,  and 
we  think  may  be  readily  understood  by 
the  apprentice  at  the  grindstone  ;  when 
the  man  of  the  axe  bears  harder, 
one  of  two  things  is  the  consequence, 
either  the  stone  makes  a  less  number 
of  revolutions  per  minute,  or  the  boy  ap- 
plies more  power.  Much  has  been  said 
relative  to  the  comparative  efficiency 
of  the  large  and  small  water-wheel, 
the  increase  of  power  necessary  to  be 
applied  to  the  large  wheel  may  also  be 
considered,  if  we  would  make  the  same 
number    of   turns.      We    will   remark, 


that  although  the  large  wheel  is  with- 
out  doubt  favorable  to  high  speed,  (pro- 
vided we  have  steam  to  handle  it,)  yet 
if  we  determine  to  obtain  great  speed 
with  a  large  amount  of  power  (and  a 
large  wheel)  from  a  bad  shape,  we  may 
get  disappointed.  We  may  make  the 
boat  bear  a  load  of  resistance  beyond 
her  strength,  and  shiver  the  wheel  into 
fragments  with  power,  and  she  may  go 
no  faster.  There  is  a  certain  amount  of 
speedadaptedtoevery  shape,and  beyond 
this  she  will  not  go  ;  but  it  does  not 
follow  that  when  the  bow,  for  example, 
has  been  driven  up  to  its  highest  speed, 
that  the  stern  has  also  attained  its 
greatest  speed.  The  bow  is  not  always 
adapted  to  the  stern,  or  the  stern  to 
the  bow  ;  indeed,  it  is  often  quite  the 
reverse;  the  most  heterogeneous  quality 
may  be  found  on  one  end,  while  the 
other  may  possess  all  that  is  desirable. 
How  often  do  we  see  steamboats  settle 
at  the  stern  when  under  way.  This  is 
owing  to  the  disparity  in  shape  of  the 
two  ends ;  one  end  being  adapted  to  a 
much  higher  speed  than  the  other. 
There  is  a  peculiar  qualification  that 
steamboats  should  possess,  in  order  to 
this  adaptation,  and  without  it  the  ends 
cannot  be  adapted  the  one  to  the  other. 
It  is  not  enough  to  know  that  the  cen- 
tre of  gravity  of  displacement  is  in  the 
centre  of  length  longitudinally,  or  that 
it  is  at  a  given   point  ;   but  we  should 


32S 


MARINE    AND    NAVAL    ARCHITECTURE. 


also  know  ifiat  nt  traverses  a  vertical 
line,  not  only  at  the  several  lines  of 
flotation,  but  from  the  base  to  the  load- 
line,  and  a  wide  departure  from  this 
track  will  be  perceptible  in  the  per- 
formance of  the  boat. 

It  does  not  follow,  from  what  has 
been  shown,  that  the  two  ends  must  of 
necessity  be  alike  ;  there  may  be  the 
widest  departure  from  sameness,  and 
yet  this  relation  still  exist  between  the 
two* ends.  It  must  be  quite  apparent 
to  the  reflective  mind,  apart  from  ex- 
perimental test,  that  if  one  line  is  adapt- 
ed to  the  element,  with  the  centre  of 
gravity  at  a  given  point  in  the  longitu- 
dinal length,  another  line  would  also 
be  equally  as  well  adapted  to  the  ele- 
ment with  this  central  point  in  verti- 
cal line  with  the  one  above  or  below, 
when  at  the  same  speed.  (Were  the 
several  sections  driven  at  a  different 
speed,  then  the  case  would  be  different; 
but  while  all  parts  of  the  boat  go  at 
the  same  speed,  and  the  element  is  of 
the  same  consistency  at  every  parallel 
of  altitude,)  experiments  have  been 
made  upon  models  that  have  shown 
the  centre  of  gravity  of  displacement 
to  sae  aft  at  the  surface  from  a  verti- 
tical  line,  but  still  there  was  a  uniform 
relation.  The  Russell  theory,  based 
on  experiments,  recognizes  those  rela- 
tions ;  those  of  Mr.  Stevens  would  also 
seem   to  corroborate    them ;    but    we 


have  less  confidence  in  those  experi- 
ments than  the  projectors  themselves. 
There  are  some  circumstances  connect- 
ed with  the  experiments  that  fail  to  fur- 
nish analogies  in  all  particulars ;  for 
example  :  a  canal  is  not  the  place  to 
try  those  experiments,  and  simply  be- 
cause the  water  is  shoal,  and  the  sheet 
narrow;  consequently,  the  bottom  and 
sides  of  the  canal  have  a  very  great  in- 
fluence upon  the  results.  While  we  as- 
sume, and  we  are  really  disposed  to  be- 
lieve, that  the  resistance  belongs  to  the 
boat,  a  very  large  share  belongs  to 
the  bottom  and  sides  of  the  canal,  which 
under  some  circumstances,  would 
amount  to  more  than  half.  Were  it  pos- 
sible to  accumulate  the  same  amount 
of  resistance  on  the  vessel  as  that  shown 
by  the  indicator,  she  would  be  torn 
asunder.  Experiments  for  quite  a 
moderate  speed  will  or  may  furnish 
data,  but  for  high  speed,  under  the  in- 
fluence of  an  extraordinary  amount  of 
power,  the  river  itself  is,  comparatively 
speaking,  too  small.  In  the  canal 
we  shall  find  that  as  soon  as  we  dis- 
turb the  water  on  the  banks,  we  com- 
mence towing  not  only  the  vessel,  but 
all  the  water  in  the  canal.  Hence  we 
say,  the  wider  and  deeper  the  river 
upon  which  experiments  are  made,  the 
more  reliable  is  the  data  furnished. 

AY  ith    regard  to  our  present   know 
ledge  of  shape  for  speed,  we  have  no 


MARINE    AND    NAVAL    ARCHITECTURE. 


329 


hesitation  in  saying,  that  a  speed  of  25 
miles  per  hour  may  be  obtained,  but 
the  mechanic  who  undertakes  the  en- 
terprise  must  be  free  from  the  tram- 
meling influences  of  captains  and  own- 
ers. With  regard  to  the  shape  of 
steamboats  for  speed,  like  other  vessels, 
much  depends  upon  the  dimensions. 
Many  men  lay  large  and  heavy 
claims  to  experience,  and  upon  this 
they  lay  a  foundation  broad  and  deep 
for  a  fine  spun  theory,  that  would  lead 
the  casual  observer  to  believe  that  nar- 
row ships  or  steamboats  would  roll  less 
than  wide  ones.  But  the  discrepancy 
in  their  theory  becomes  apparent,  when 
we  remember  that  the  advocates  for 
wide  vessels  do  not  demand  a  greater 
area  of  load-line  than  those  who 
adhere  to  narrow  vessels  ;  the  dif- 
ference lies  just  here  :  the  advocate  for 
narrow  vessels  depends  on  dimensions 
alone,  while  the  advocate  for  more 
beam  bases  his  claims  for  beam  as  a 
means  of  obtaining  the  required  shape  : 
he  does  not  require  beam  for  the  pur- 
pose of  extending  it  from  one-half  to 
two-thirds  of  the  length  of  the  vessel  ; 
he  requires  more  beam  than  is  usually 
given  for  the  purpose  of  making  a 
round  side  line  from  the  line  of  flota- 
tion downward.  If  proof  were  re- 
quired of  the  truth  of  the  assertion  we 
have  made,  we  refer  to  the  fact  of  the 
increased  stability  of  our  ocean  steam- 


ers, when  the  coal  remains, in  the  side 
bunkers  and  is  used  out  of  the  ends  of 
the  vessel  first ;  and  on  the  contrary, 
when  the  coal  is  used  out  of  the  side 
bunkers  first,  and  left  in  the  ends,  the 
vessel  rolls  and  becomes  unsteady,  with 
first  one  wheel  immersed,  and  then 
the  other.  We  think  those  who  ad- 
vocate narrow  vessels  for  stability  will 
find  it  difficult  to  digest  this  fact,  in 
connection  with  the  assumption  that 
because  a  vessel  has  the  apex  of  the 
sea  on  one  side,  the  trough  must  of 
necessity  be  on  the  other,  and  that  the 
leverage  is  greater  in  proportion  to  any 
extension  of  the  breadth,  and  the  ves- 
sel must  of  necessity  roll  more.  But 
there  is  another  fact  that  belongs  to 
this  question  of  the  sea  on  one  side 
and  the  trough  on  the  other  ;  the  ad- 
vocates of  narrow  vessels  must  remem- 
ber, that  the  stability  depends  as  we 
have  shown  upon  the  altitude  of  the 
centre  of  effort;  the  higher  this  point, 
the  more  stable  the  vessel,  provided 
the  shape  and  stowage  do  not  conflict 
with  the  known  laws  that  govern  sta- 
bility in  these  particulars.  We  say 
that  it  is  only  those  who  take  a  superfi- 
cial view  of  the  matter  who  advocate 
narrow  vessels,  inasmuch  as  the  known 
laws  of  geometrical  science,  in  connec- 
tion with  experience  versus  experi- 
ments of  a  tangible  nature,  is  against 
them.     With  regard  to  the  weight  oi 


4-2 


380 


MARINE    AND    NAVAL    ARCHITECTURE. 


steamboats,  it  seems  to  us  that  some 
remarks  would  be  in  keeping.  When 
great  speed  is  the  desired  object  in 
building  steamboats,  all  unnecessary 
weight  should  be  dispensed  with  ;  and 
we  would  here  remark,  that  the 
strength  of  steamboats  for  river  navi- 
gation should  principally  rest  in  the 
bottom,  when  the  engine  is  low  pres- 
sure, and  secured  to  the  same.  The 
distribution  of  timber  for  strength  is  a 
matter  that  requires  the  exercise  of 
some  considerable  amount  of  mechani- 
cal skill  ;  centre,  engine,  sister  and 
bilge  keelsons  are  of  the  utmost  im- 
portance to  the  steamboat  having  her 
engines  in  the  hold,  and  these  should 
be  square  fastened  with  blunt  bolts. 
There  arc  many  parts  of  steamboats 
and  other  small  vessels  where  screw- 
bolts  should  be  used,  where  the 
amount  of  surface  through  which  the 
bolt  is  to  be  driven  is  not  commensu- 
rate with  the  strength  of  the  material 
or  the  strength  required.  An  easy  or 
light  draught  of  water  being  often  in- 
dispensable to  river  navigation,  it  is 
very  generally  sought  in  the  shape  at 
the  expense  of  speed,  whereas  it  should 
have  been  looked  for  in  the  dimensions 
and  weight  of  material;  for  very  light 
draught  iron  boats  are  superior  to  those 
of  wood.  It  would  be  a  difficult  mat- 
ter to  build  a  boat  of  timber  of  any 
considerable  size  and  sufficiently  strong, 


that  would  navigate  a  stream  of 
water  13  inches  deep,  and  yet  the 
same  may  and  has  been  accomplished 
with  iron.  A  larger  amount  of 
strength  with  the  same  weight,  or  the 
same  amount  of  strength  with  less 
weight,  may  be  obtained  of  iron  than 
of  wood.  With  regard  to  the  resist- 
ance of  the  two  kinds  of  materials, 
timber  presents  more  than  iron  ;  hence 
it  follows,  that  if  two  steamboats  were 
built  alike  in  shape,  and  brought  to  the 
same  draught  of  water,  and  the  same 
amount  of  power  applied  to  both  boats, 
the  iron  boat  would  be  found  to  be 
faster  than  the  one  built  of  wood  ;  the 
reasons  will  appear  obvious  if  we  but 
reflect  that  the  timber  is  porous,  and 
that  the  molecules  or  particles  of  water 
rilling  the  orifice  must  be  rent  asunder 
in  their  collision  with  those  of  the  ex- 
terior surface  of  the  passing  boat. 
This  separation  exhausts  an  enormous 
amount  of  power ;  the  proportions  of 
which  may  be  judged,  if  we  but  wit- 
ness the  effect  when  the  operation  is 
in  accordance  with  the  known  laws  of 
hydraulics  :  let  a  pipe  of  any  given  size 
be  the  conductor  of  a  stream  of  water, 
it  may  be  to  convey  the  stream  in  longi- 
tudinal or  vertical  directions,  it  matters 
not  which,  the  pipe  may  be  assumed 
to  be  of  parallel  opening  its  whole 
length;  we  may  now  determine  precise- 
ly the  arhount  of  water  that  it  will  dis- 


I 


MARINE  AND  NAVAL  ARCHITECTURE. 


331 


charge  per  minute  with  a  given  head, 
or  with  a  reservoir  of  a  determinate 
altitude  ;  the  pipe  may  now  be  enlarged 
in  any  part  of  its  length  between  the 
ends,  and  again  the  discharge  may  be 
determined  per  minute,  and  it  will 
be  found  that  it  is  less,  although 
the  pipe  has  been  made  larger,  and 
is  placed  in  the  same  position  as  be- 
fore, under  the  same  head  of  water. 
It  is  the  disruption  of  the  particles  that 
remain  in  the  recess  of  the  pipe  that 
checks  the  passage  ;  so  with  the  plank 
on  the  steamboat's  bottom  ;  and  can 
only  be  counteracted  by  metal  sheath- 
ing, which  for  shoal  water  is  difficult  to 
keep  properly  adjusted.  It  is  in  this 
particular  that  iron  presents  (for  speed) 
a  better  surface  than  wood.  There  are 
other  circumstances  under  which  iron 
as  a  material  for  building  vessels  ex- 
hibits its  advantages  over  that  of  wood; 
in  the  West  Indies  and  some  parts  of 
South  America,  and  even  the  southern 
parts  of  the  United  States,  timber  rots 
in  a  very  short  time,  in  consequence 
of  the  peculiar  state  of  the  atmosphere 
generating  deleterious  gasses  rapidly, 
which  causes  wooden  vessels  to  rot  in  a 
very  short  time  ;  hence  we  say,  that 
for  low  latitudes  where  vessels  cannot 
be  abundantly  ventilated,  they  should 
be  built  of  iron,  if  durability  is  a  con- 
sideration. The  principal  objection  to 
their  introduction  on  an  exte^ive  scale 


in  this  country,  is  their  cost,  inasmuch 
as  the  expense  ranges  from  25  10  30 
per  cent,  more  than  wood  ;  this  must 
prove  a  barrier  to  the  construction  ot 
large  sailing  vessels  of  iron  in  this 
country,  where  timber  is  abundant, 
and  the  chances  remain  that  a  vessel 
may  pay  her  first  cost  with  interest, 
wear  and  tear,  long  before  she  is  com- 
pletely rotten. 

In  England,  iron  vessels  of  all  sizes, 
and  almost  all  kinds,  have  been,  and 
continue  to  be,  built.  English  authors 
have  endeavored  to  show  all,  and  even 
more  than  all,  the  advantages  that  ac- 
crue from  building  of  iron  ;  but  while 
we  are  quite  willing  that  their  argu- 
ments should  be  heard,  we  are  dis- 
posed to  correct  any  error  into  which 
they  may  have  fallen,  in  their  eager 
haste  to  show  the  superiority  of  iron 
over  wood. 

Mr.  Grantham,  President  of  the 
Polytechnic  Society  of  London,  in  a 
work  entitled,  "  Grantham  on  Iron,  as 
a  Material  for  Ship-building,"  sets  down 
as  one  of  the  advantages,  the  correct- 
ness with  which  the  draught  of  water 
may  be  ascertained,  in  proof  of  which 
an  instance  is  cited,  in  which  the 
draught  of  water  was  not  determined 
within  24  feet  on  a  steamer  built  of 
wood. 

Lest  the  reader  should  be  led  astray 
by  similar  statements,  we   would  add, 


332 


MARINE    AND    NAVAL    ARCHITECTURE. 


that  had  the  builder  of  the  steamer  in 
question  taken  a  few  lessons  in  the 
United  States,  he  would  have  been  able 
to  have  approximated  the  draught  of 
water  of  any  vessel  before  launching, 
without  goinjj  into  the  calculation. 
That  the  precise  or  exact  draught  of 
water  may  be  more  readily  determined 
when  the  material  of  construction  is 
iron,  cannot  be  doubted  ;  but  we  are 
persuaded  that  a  mechanic  who  had 
never  before  seen  a  vessel,  would  be 
able  to  mark  her  draught  within  2*  feet 
without  the  use  of  figures,  or  quite  as 
near  as  the  case  cited. 

Iron  steamboats  possess  another  ad- 
vantage which  should,  we  think,  re- 
commend them  for  the  Mississippi  and 
other  Western  rivers.  The  advantage 
alluded  to  consists  in  the  water-tight 
bulk  heads,  which  effectually  prevents 
the  boat  from  sinking,  even  though 
one  part  should  be  snagged  and  filled 
with  water.  The  corrosive  quality 
that  stands  connected  with  the  use  of 
iron  for  vessels  to  navigate  the  ocean, 
in  connection  with  their  cost,  must  be 
a  drawback  on  their  extensive  use. 

As  it  regards  shape  for  high  speed  in 
river  steamboats,  we  desire  to  stand 
fully  committed,  whatever  may  be  the 
strength  of  that  tide  of  influence,  made 
up  of  prejudices,  and  completely  in- 
terwoven with  the  subject  of  steam 
river  navigation.     First,  there    is    an 


endless  variety  in  opinions  with  regard 
to  the  proper  shape  for  high  speed, 
apart  from  the  proportionate  principal 
dimensions.  It  has  been  set  down  as 
an  axiom,  that  the  highest  degrees  of 
speed  were  only  attainable  by  the  long- 
est boats  having  the  proportionate 
amount  of  power;  but  what  that  pro- 
portion amounted  to  has  never  been 
defined.  Almost  from  the  commence- 
ment of  that  spirit  of  rivalry  that  has 
marked  the  progress  of  steam  on  the 
Hudson  perhaps  more  than  on  any 
other  river  in  the  world,  there  has 
been  a  disposition  manifested  by  the 
organization  of  companies  to  monopo- 
lize the  travelling  facilities  on  this  ma- 
jestic river ;  but  not  the  least  promi- 
nent feature  of  these  aggrandizing  ef- 
forts is,  that  of  claiming  that  their 
knowledge  was  commensurate  with 
their  experience,  and  their  experience 
with  the  amount  of  means  expended 
and  efforts  made  to  maintain  the  su- 
premacy. At  intervals,  however,  in" 
the  history  of  those  efforts,  there  has 
arisen  some  indomitable  spirits  who 
have  dared  to  undertake  the  construc- 
tion of  steamboats  for  high  speed  of 
much  smaller  size,  and  not  unfrequent- 
ly  have  they  borne  off  the  palm  of  vic- 
tory over  their  more  powerful  competi- 
tors. Among  those  thus  successful, 
staiuls  the  steamboat  REINDEER, 
the  lines  of  which  are  shown  on  Plate 


MARINE    AND    NAVAL    ARCHITECTURE 


333 


23.  This  boat,  built  during  the  pres- 
ent year,  1S50,  by  Mr.  Thomas  Colyer, 
although  not  of  mammoth  proportions, 
(and  consequently  not  of  gigantic  size,) 
is  superior  for  speed,  and  is  doubtless 
at  this  time  the  fastest  wooden  river 
bmit  of  her  length  in  the  United  States. 
She  has  the  wave-line  bow,  and  it 
would  be  found  a  difficult  matter  to  ob- 
tain an  excess  of  speed  in  the  same 
length  with  the  same  amount  of  power, 
without  reducing  the  weight,  (which 
it  will  be  seen  is  by  no  means  great.) 
The  Reindeer  has  been  termed  a  24 
mile  boat  ;  that  is  to  say,  she  can 
run  24  miles  in  an  hour,  in  still  water, 
without  much  extra  effort  by  way  of 
making  steam. 

Her  dimensions  are  as  follows:  length, 
260  feet ;  breadth,  34.0S  feet  ;  depth, 
midships,  from  base  line  to  deck  line, 
round  of  the  beam  deducted,  9.75  feet ; 
area  of  her  immersed  midship  section, 
119  square  feet  ;  diameter  of  cylinder, 
56  inches;  stroke  of  piston,  12  feet; 
diameter  of  water-wheel,  34  feet  ;  face 
of  wheel,  9  feet  6  inches  ;  width  of 
bucket,  24  inches,  calculated  to  dip  9 
inches  below  the  surface.  Her  engine 
is  that  known  as  the  vertical  beam  en- 
gine ;  balance  valves  with  Stevens's  cut- 
oil*;  its  weight,  in  connection  with 
that  of  the  gallows  frame,  (which  is 
set  down  at  16,000  pounds.)  is  com- 
puted at   201,019  pounds;   the  water- 


wheels,  39,300  pounds.  Ttie  weight 
of  the  boiler  equals  87,S47  pounds ; 
the  water  in  the  same,  91,847  pounds; 
displacement  or  weight  of  the  boat  at 
4  feet  draught  of  water,  447  tons  417 
pounds  ;  weight  of  engines  and  boilers, 
with  water  in  the  same,  187  tons  1,133 
pounds;  weight  of  joiner's  work,  63 
tons  111  pounds;  weight  of  furniture 
and  outfit,  17  tons  320  pounds.  Total 
weight  of  engines,  boilers,  joiner's  work, 
furniture,  and  outfit,  267  tons  1564 
pounds  ;  leaving  for  the  weight  of  the 
boat  179  tons  1090  pounds,  which  is 
a  very  close  approximation  to  the 
exact  weight  of  the  hull. 

In  connection  with  the  speed  of 
steamboats,  the  power  applied,  and 
the  manner  of  computing  it,  stands  in- 
timately connected  with  the  subject. 
In  Europe  very  generally,  and  in  this 
country  to  some  extent,  the  power  of 
steam  vessels  is  computed  by  horse- 
power. The  great  bulk  of  operative 
mechanics  do  not  fully  understand  this 
manner  of  computing  power,  and  we 
have  ever  regarded  it  as  loose  and  in- 
definite. There  is  a  distinction  (that 
is  not  always  regarded)  between  the 
pressure  indicated  by  the  steam  guage 
at  the  boiler,  and  the  effective  power 
applied  as  resistance  at  the  water. 
The  principal  c;iuse  is  found  in  the 
loss  occasioned  by  the  friction  of  the 
journals,   and   in    the  transfer   of  the 


334 


MARINE    AND    NAVAL    ARCHITECTURE. 


steam  from  the  boiler  to  the  cylinder. 
The  sum  total  of  this  is  set  down  at 
.65.  The  horse-power  is  determined  in 
the  following' manner:  multiply  the 
area  of  the  piston  by  the  pressure  of 
steam,  as  shown  by  the  guage  per 
square  inch,  plus  the  pressure  of  the 
atmosphere,  and  that  sum  by  the  velo- 
city of  the  piston  per  minute,  divide 
by  33,000,  (which  is  the  weight  in 
pounds,  it  is  assumed  that  a  horse  can 
raise  one  foot  high  in  one  minute,)  and 
multiply  the  quotient  by  .65,  which 
will  give  the  effective  power  for  steam 
engines.     Example  : — 


Am  Pressure 

a     x      p 


Velocity  of 
PtotOD 


x  v  x  .65=  Horse- 
power effectual.  When  the  steam  is 
cut  off  at  half  stroke  (or  when  the  sup- 
ply of  steam  is  withheld  at  half  the 
stroke)  in  the  cylinder,  there  is  another 
drawback  which  reduces  the  effective 
power  from  unit  to  .847,  inasmuch  as 
.S47  is  found  to  be  the  multiplier  for 
2;  this  may  be  readily  understood  if 
we  but  remember  that  in  cutting1  off 
the  supply  of  steam  at  half  stroke,  the 


only  power  that  can  be  obtained  for 
the  remainder,  or  the  other  half  of  the 
stroke,  must  be  obtained  from  the  ex- 
pansion of  the  steam,  which  loses  part 
of  its  heat,  (and  consequently  part  of 
its  power,)  in  the  expansion  ;  hence 
we  have  fl  tt  ■*■  T=2,  the  multiplier 
for  which  is  .S47.  Suppose  the  di- 
ameter of  a  cylinder  to  be  72  inches, 
the  stroke  of  piston  12  feet,  pressure 
of  steam  per  guage,  40  pounds,  as 
shown  by  the  steam  guage,  cut  off  at 
half  stroke,  (or  half  the  length  of  the 
cylinder,)  number  of  revolutions  per 
minute  22,  required  the  horse-power. 
First  find  the  mean  effective  power 
per  square  inch  in  the  manner  we 
have  already  shown,  the  value  of  2  be- 
ing the  multiplier,  which  is  .S47,  '(see 
Haswell, 

Pressure  Atmosphere 

40  lbs.  +  14.7  =  54.7  x. 847  =  46.33 

pounds  as  the  mean  effective  pressure 
in  the  cylinder  for  each  square  inch  of 
its  area.  To  find  the  horse-power,  find 
the  area  of  piston — 


Feel  per 
minute. 


EfiVciivo 
horse-power* 

4071.5x  46.33=188632.595x528=99598010.16- 33000=3018x.65  =  1961.'i 


Some  farther  expositions  in  relation 
to  the  water-wheel  of  river  steamboats 
may  be  necessary.  Some  boats  have 
been  found  to  have  attained  a  greater 
Speed  when  brought  down  in  the  water 


by  freight  or  passengers  several  inches, 
than  they  did  when  light,  thus  afford- 
ing the  most  conclusive  evidence,  that 
had Ujie  •  wheel  been  larger  the  boat 
would  have  performed  better,  inasmuch 


.V 


*mr. 


.  «p 


MARINE    AND    NAVAL    ARCHITECTURE 


335 


as  the  same  amount  of  power  would 
have  been  applied  with  less  steam,  for 
it  should  not  be  forgotten  that  a  bulk 
of  steam  equal  to  the  cubical  contents 
of  the  cylinder  is  lost  at  every  revolu- 
tion, even  though  we  cut  off  at  half 
stroke  ;  hence,  it  is  plain,  that  unless 
an  even  pressure  is  kept  in  the  boiler 
there  is  a  loss  of  power,  and  more 
would  be  gained  by  increasing  the  size 
of  the  wheel  if  we  would  keep  the  pow- 
er at  the  same  altitude.  But  there  is 
another  view  to  be  taken,  which  aug- 
ments the  advantage  of  large  wheels  in 
diameter  ;  they  operate  more  direct  on 
the  water,  and  although  more  power  is 
required  to  turn  them,  or  to  make  the 
same  number  of  revolutions  in  a  given 
time,  yet  all  the  available  power  of  the 
boiler  and  engine  is  applied  at  the 
water  with  less  difference  between  the 
speed  of  the  wheel  at  its  periphery  and 
the  boat,  and  consequently,  less  slip  or 
slide  of  the  bucket.  We  would  not  be 
understood  to  say,  that  the  slower  the 
wheel  the  faster  the  boat,  but  we  do 
say,  that  when  the  wli§&fr  turns  fast 
enough  to  reduce  the  pressure  in  the 
boiler,  we  require  more  wheel  or  more 
boiler.  This  may  be  clearly  illustrated 
in  the  steamboat  at  the  dock  with  the 
engine  in  operation — the  ^flflwe  pres- 
sure of  steam  will  not  turn  the  wheel 
as  fast  as  when  the  boat  moves  ahead; 
and  while  the  boat  remains  at  the  dock 


we  may  have  steam  enough,  but  loose 
her  fasts  and  let  her  go,  and  we  soon 
see  the  difference.      This  leads   us  to 

t 

another  truth  that  should  also  be  re- 
membered— the  faster  the  boat  itself  is 
capable  of  being  driven,  the  less  re- 
sistance with  the  same  sized  wheel,  and, 
as  a  consequence,  the  wheel  will  turn 
faster  with  the  same  power  and  use 
more  steam;  so  that  as  we  diminish  the 
resistance  on  the  boat,  we  must  in- 
crease it  on  the  wheel,  to  keep  the  same 
amount  that  a  slower  boat  would  have. 
We  have  been  led  to  these  remarks, 
upon  witnessing  the  wholesale  blun- 
ders made  upon  river  steamboats  in  re- 
lation to  the  proportion  existing  be- 
tween the  boiler  and  wheel,  by  men 
whose  claims  to  a  registry  in  the  cal- 
endar of  common  sense,  (in  this  as 
well  as  in  other  matters,)  were  recog- 
nized on  all  sides  apart  from  a  know- 
ledge of  the  science  of  mechanics. 
It  should  also  be  remembered  that  a 
saving  of  steam  is  a  saving  of  fuel,  and 
a  saving  of  fuel  is  a  saving  of  dollars. 
Most  of  the  engines  of  the  river  boats 
of  the  United  States,  excepting  those 
of  the  Mississippi,  are  high  pressure 
condensing  engines,  although  denomi- 
nated low  pressure — a  term  belonging 
properly  to  those  engines  only  that 
carry  a  pressure  in  the  boiler  not  ex- 
ceeding that  of  the  atmosphere,  or  15 
pounds  per  square  inch. 


«^ 


'  . 


.'V* 


-. 


33G 


MARINE    AND    NAVAL    ARCHITECTURE 


Much  might  be  said  in  relation  to 
Stevens's  new  plan  to  increase  the 
speed  of  steamboats,  by  interposing  a 
stratum  of  air  between  the  flat  surface 
of  the  bottom  and  the  water.  Little, 
however,  is  known  in  relation  to  the 
final  results  of  this  experiment  by 
Mr.  Stevens  himself;  but  this  much 
appears  to  be  quite  conclusive,  that  he 
has  succeeded  in  securing  a  rate  of 
speed  superior  to  that  of  any  wooden 
boat  of  equal  length  on  the  Hudson  ; 
and  this  has  been  secured  upon  an 
iron  boat  of  some  270  or  2S0  feet  long, 
of  a  shape  the  most  heterogeneous  for 
high  speed.  Mr.  Stevens  has  seen  fit 
thus  far  to  divulge  but  little  in  detail 
of  his  method  of  operations,  although 
the  right  to  the  invention  has  been 
patented  both  in  Europe  and  America 
some  years  since ;  as  a  consequence 
we  are  unable  to  anticipate  what  might 
be  accomplished,  provided  the  inven- 
tion could  be  applied  to  a  good  shape 
for  speed. 

Having  accomplished  our  purpose 
in  relation  to  steamboats,  we  shall  pro- 
ceed to  inquire  what  are  the  most  es- 
sential properties  required  for  steam- 
ers suited  to  navigate  the  ocean.  Our 
readers  are  doubtless  familiar  with  the 
achievements  of  American  steam-ships, 
and  it  seems  only  necessary  that  we 
should  show  the  qualities  requisite  to 
place  the  ocean  steamer  at  the  head  of 


the  list  of  wondrous  achievements 
consequent  upon  American  genius, 
having  already  shown  that  it  is  to 
the  United  States  that  the  honor  be- 
longs of  first  embarking  in  this  noble 
enterprise. 

The  silent  observer  beholds  with 
wonder  and  admiration  not  only  the 
speed,  but  the  regularity  of  steam-ships 
as  they  furrow  a  trackless  path  be- 
tween the  Old  and  New  World,  not- 
withstanding the  ocean  may  be  lashed 
into  furious,  rugged,  and  frightful  pre- 
cipices by  the  friction  of  the  wind  ;  yet 
she  seems  to  tarry  not,  her  course  is 
onward,  as  if  to  hurl  defiance  at  the 
watery  blast.  Here  lies  the  great  se- 
cret of  success  in  steam-ships,  viz. : 
their  regularity  in  the  length  of  their 
voyages,  while  running  at  the  same 
place,  or  plying  between  the  same 
ports.  If  storms  retard  their  progress 
so  that,  for  example,  the  voyage  be- 
tween New- York  and  Liverpool  varies 
from  11  to  13  days,  they  cannot  be 
depended  on,  and  in  this  particular 
have  but  little  advantage  over  the  sail- 
ing ship ;  for  little  doubt  exists  that 
there  are  sailing  ships  now  built  that 
would  not  vary  more  than  10  to  12 
days  in„the  length  of  their  voyage  for 
a  year  at  a  time.  The  performance  of 
the  Ca'nton  packet  ship  Sea  Witch 
abufl#antly  warrants  us  in  this  asser- 
tion; and  her  last  voyage  to  San  Fran- 


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J&IARINE    AND    NAVAL    ARCHITECTURE. 


337 


cisco  from  this  city  in  97  days,  shows 
that  there  is  much  room  for  improve- 
ment before  a  steam-ship  could  per- 
form a  similar  voyage. 

It  may  be  said  that  steam-ships  are 
not  designed  for  long  voyages  ;  this  we 
admit,  in  their  present  state  of  ad- 
vancement;  nor  are  they  best  adapted 
for  short  voyages,  unless  regularity  be 
stamped  on  their  performances  or 
equality  on  the  length  of  their  trips. 
Steam-ships  are  costly  and  expensive, 
and  unless  they  fully  answer  the  object 
designed,  they  are  unprofitable,  and  it 
does  not  require  much  sagacity  to  dis- 
cover that  as  soon  as  they  cease  to  pay, 
they  will  be  abandoned  for  other  than 
mail  and  war  purposes. 

It  must  be  quite  apparent  that  steam- 
ships cannot  successfully  compete  with 
sailing  ships  for  freighting  purposes, 
for  this  reason,  if  they  have  any  con- 
siderable capacity  for  cargo,  they  are 
liable  to  detention  on  account  of  storms, 
which  will  lengthen  the  voyage,  and 
render  it  of  uncertain  length.  The 
merchant  will  not  pay  extra  freight 
unless  he  is  certain  that  his  goods  will 
be  conveyed  to  their  port  of  destina- 
tion within  a  definite  time,  and  we  at 
once  discover  that  the  steam-ship  has 
not  only  more  expense  to  encounter, 
but  carries  less  freight,  in  consequence 
of  the  engines  and  coal  occupying  a 
large  portion  of  her  capacity  for  freight. 


Thus  we  discover  that  to  make  ^steam- 
ship profitable  for  freighting  purposes, 
she  is  unfit  for  the  conveyance  of  pas- 
sengers and  the  mail,  inasmuch  as  pas- 
sengers and  letters  require  a  speedy 
conveyance  ;  hence,  it  must  be  plain 
even  to  the  casual  observer,  that  the 
most  desirable  quality  in  steam-ships  is 
speed,  but  to  acquire  this,  we  must  sac- 
rifice many  of  the  hereditary  notions 
that  pertain  to  sailing  vessels.  An 
ocean  steam-ship,  in  crossing  the  At- 
lantic, should  never  vary  more  than  a 
few  hours  in  the  length  of  her  voyages  ; 
this  would  inspire  confidence  in  this 
class  of  vessels,  and  secure  all  the  pas- 
sengers. To  accomplish  this  they  re- 
quire a  reserve  of  power  of  at  least  one- 
third  of  the  entire  power  of  the  engine  ; 
this  power  should  be  applied  when  the 
winds  are  adverse,  to  enable  the  ship 
to  maintain  an  equilibrium  in  speed. 
It  is  vain  and  futile  to  think  of  doing 
this  unless  the  ship  be  very  sharp  lon- 
gitudinally, so  much  so  that  at  her 
highest  speed  she  will  not  generate 
even  the  smallest  wave.  It  has  been 
found  that  instead  of  applying  more 
power  in  a  storm  or  gale  of  wind,  it  is 
necessary  to  apply  less  to  save  the  ship. 
The  full  bow  generates  resistance  to  the 
wave,  and  causes  it  to  strike  with  de- 
structive force,  and  between  the  force 
of  the  wave  driving  in  the  direction  of 
the  stern,  and  the  engine  driving  in  the 


43 


338 


MARINE    AND    NAVAL    ARCHITECTURE. 


direction    of  the  bow,  the  ship  labors 
in  every  joint  if  the  equality  of  power 
is  maintained,  and  the  consequence  is, 
the  power  must  be  reduced  ;    whereas, 
had   tlie    ship    been    as    sharp    as    she 
should   have  been    longitudinally,   she 
might  have  not  only  braved  the  storm, 
but  maintained  her  original  speed  by 
the  use  of  the  reserve  power.     We  say 
that  ocean  steam-ships  cannot  be  made 
too  sharp.     If  the  bow  be  so  sharp  that 
it  has  no  buoyancy,  or  very  little,  it  can 
be  sustained,  but  if  it  is  full,  it  cannot 
be  kept   down   when  submerged  in  a 
sea  ;   the  consequence  is,  the  engine  is 
unsupported — the  ship  being  sustained 
by  the  ends,  and  very  soon  shows  the 
result  by    straining  both   the  ship  and 
the    engine.      That  part  of  the  ship  in 
which  the  engines  and  boilers  are  lo- 
cated, must  be  supported  by  the  water  ; 
the  engines  have  their  own  work  to  do 
without    holding    the    ship    when    the 
water   refuses  to  do  it.     It   has  been 
said  that  when  the  bow  is  very  sharp 
it  is  also  very  wet — that  the  sea  makes 
too  free  a   use  of  the  deck  forward. 
This  need  not  be  so ;  the  bow  is  im- 
properly formed  when  this  is  the  case. 
The  sea  may  be  parted  in  such  man- 
ner as  to  throw   off  its  bulk  from  the 
ship. 

It  is  held  as  an  axiom  that  a  fist 
ship  must  of  necessity  be  a  wet  ship. 
That  fast  sailing  ships  are  in  general 


wet,  cannot  be  denied,  but  it  is  in  most 
cases  consequent  upon  an  improper  dis- 
tribution of  sail;  the  leverage,  however, 
is  different  in  the   steam-ship,  the  bow 
is  not  depressed,  but  is  raised.     If  the 
steam-ship  is  as  sharp  as  she  should  be, 
no  matter  how  much  power  is  applied, 
she  will    not  herself  make  the  wave 
upon  which  she  rises.     The  less  motion 
the  ship  has,  the  faster  she  will  go,  and 
not  only  so,  but   the  safer  she  will  be, 
inasmuch  as  it  is  the  roll  and  pitch  that 
endangers  the   ship    by    straining    the 
engines,  and  is  so  annoying  to  passen- 
gers.     Hence   we  say,  let   the  bow  be 
long,  and  as  sharp  as  the  length  of  the 
ship  will  admit  of;   and  in  order  to  keep 
it  dry,  let  the  flare  be  carried  close  up 
to  the  rail,  in  order  that  the  sharpness 
may  be  continued  above  the  line  of  flo- 
tation.     In   addition   to  this,  the  bow 
should  be  deeper  than  the  stern;    that 
is  to  say,  from  the  line  of  flotation  to 
the  rail  on  the    bow  should  be  on   a 
steamer  of  any  considerable  size  (and 
one  less  than  2000  tons  is  a  small  af- 
fair) from  5  to  6  feet  higher  than  that 
of  the  stern  ;  and  if  the  line  of  flotation 
is  sharpest  at  the   commencement  of 
the  bow,  and  gradually  fills  out  until  it 
reaches  the  middle  of  the  same,  from 
lyhich    point   it   again    commences  to 
sharpen,  and  continues  to  do  so  until 
it  reaches  the  greatest  transverse  sec- 
tion, (which  may  be  aft  of  the  centre  of 


MARINE    AND    NAVAL    ARCHITECTURE. 


339 


length,)  and  as  soon  as  we  reach  the 
extreme  breadth,  commence  losing 
the  same  as  we  approach  the  stern  ;  in 
the  same  maimer  we  shall  accomplish 
what  we  aim  at  as  far  as  the  line  of 
flotation  has  an  interest  in  this  matter. 
Thus  we  discover  that  the  bow,  as  de- 
scribed, extends  from  the  stem  to  the 
®  frame,  or  to  the  greatest  transverse 
section,  and  that  the  sharpest  part  of 
the  bow  is  at  the  wood  ends ;  this  is  a 
property  of  hollow  parallel  lines  to  the 
line  of  flotation,  while  the  round  line, 
no  matter  how  sharp,  makes  the  fullest 
part  of  the  bow  at  the  wood  ends  ;  this 
causes  the  water  to  rise  and  generate 
a  wave,  which  is  continued  when  the 
ship  is  driven  at  any  considerable  speed; 
in  a  word,  the  lines  of  a  steamboat  or 
ship  should  have  no  sameness.  As 
soon  as  the  greatest  breadth  has  been 
reached,  we  should  commence  retiring 
at  once  toward  the  end  ;  but  this  shape 
contemplates  stability  lengthwise,  and 
is  consequent  to  some  extent  upon  di- 
mensions. The  draught  of  water  and 
weight  to  be  sustained  must  be  brought 
into  the  account,  or  we  reckon  without 
our  host.  The  breadth  must  also  be 
considered,  and  for  stability  we  require 
more  than  the  usual  proportion  for 
sailing  ships,  as  we  have  shown  ofi 
page  43,  popular  prejudice  to  the  con- 
trary notwithstanding. 

Our  remarks  upon   rolling,  and  the 


cause,  have  been  clear  and  conclusive 
in  our  own  judgment,  and  if  experi- 
ence is  any  test,  we  are  also  supported 
in  a  good  degree.  There  is,  however, 
another  feature  connected  with  a  good 
degree  of  breadth  for  steam-ships  that 
should  settle  the  point  in  the  minds  of 
those  whose  experience  is  hereditary 
as  well  as  their  opinions.  It  is  admit- 
ted on  all  hands  that  an  ocean  steam- 
ship should,  if  possible,  have  the  same 
dip  to  her  wheel  the  whole  length  of 
the  voyage ;  in  other  words,  if  the 
wheel  has  the  right  amount  of  dip  at 
the  commencement  of  the  voyage,  and 
has  less  at  the  termination,  it  does 
not  have  enough — consequently  the 
nearer  this  dip  at  the  commencement 
and  termination  of  the  voyage  can  be 
equalized,  the  faster  the  ship  will  go. 
The  question  at  once  arises,  what  has 
this  to  do  with  the  breadth  of  the  ship  ? 
We  say  much  ;  800  tons  of  coal  re- 
moved from  a  narrow  ship  with  a 
known  displacement,  will  raise  her 
higher  out  of  the  water  than  if  the  ship 
were  wider  with  the  same  displace- 
ment. There  is  nothing  mysterious 
about  this  ;  two  ships  of  the  same  dis- 
placement, the  one  narrow  and  the  other 
wide,  the  narrow  ship  in  discharging 
500  tons  is  raised  out  of  water  6  inches 
more  than  the  wide  ship,  and,  as  a 
consequence,  has  6  inches  less  dip  to 
her  wheel,  which,  had  the  two  ships 


340 


MARINE    AND    NAVAL    ARCHITECTURE, 


an  equal  amount  of  resistance,  power 
and  speed  would  place  the  wide  ship 
in  advance  of  the  other  at  the  termi- 
nation of  a  voyage  together,  and  al- 
though  the  narrow  ship  might  secure 
an  equal  amount  of  resistance  at  the 
wheel,  by  securing  the  same  dip,  it 
would  be  at  the  expense  of  more  re- 
sistance on  the  ship,  on  account  of 
water  she  might  pump  in  tanks  to 
equalize  the  dip  of  the  wheel ;  for  it  is 
plain,  that  if  she  burned  less  coal,  she 
would  make  less  steam,  and,  conse- 
quently, would  have  less  power ;  for 
after  all  that  can  be  said  about  power 
on  steam  vessels,  the  steam  is  the 
power,  and  a  given  amount  of  the  same 
kind  of  fuel  will,  under  the  same  cir- 
cumstances, make  a  given  amount  of 
steam.  Thus  the  adherents  to  narrow 
steam-ships  are  driven  to  the  necessity 
of  starling  with  more  dip  than  they 
should  have,  and  even  more  wheel  than 
they  can  properly  manage  to  continue 
so,  until  the  ship  has  been  lightened  by 
the  consumption  of  coal,  or  else  at  the 
termination  of  the  voyage  the  wheel  is 
making  foam  on  the  surface  of  the 
water,  and  rolling  alternately  each 
wheel  out  with  little  effect,  straining 
the  engine  to  no  purpose. 

From  what  has  been  shown,  it  must 
have  been  discovered  that  it  is  all-im- 
portant to  determine  the  diameter,  and, 
as  a  consequence,  the  dip  of  the  wheel, 


before  we  commence  building  the  ship, 
and  learn  before  we  adopt  the  model, 
even  if  it  be  made,  how  much  the  con- 
sumption of  the  necessary  fuel  will 
lighten  us,  and  what  dip  will  remain, 
and  if  we  find  it  necessary,  increase 
the  proportion  of  breadth  fully  up  to 
what  has  been  shown  on  page  43. 
We  need  have  no  fears  in  relation  to 
the  roll  of  the  ship;  the  altitude  of  the 
centre  of  effort,  the  location  of  the 
centre  of  gravity,  and  the  shape  of  the 
bilge  determine  this  quality.  We,  as 
Americans,  have  been  led  into  this  er- 
ror of  narrow  steam-ships  by  England  ; 
and  surely  no  steam-ships  roll  more 
than  the  Cunard  line,  with  the  fullest 
part  of  their  line  of  flotation  at  the  two 
extremities  ;  they  hang  by  the  ends, 
(as  if  in  a  turning  lathe,)  and  roll  from 
side  to  side,  taking  the  water  over  the 
rail  forward  in  astonishing  quantities. 
England,  although  a  commercial 
nation,  and  as  her  Premiers  and  lead- 
ing statesmen  have  boldly  announced, 
her  policy  is  strictly  commercial,  yet 
her  hereditary  institutions  have  stamp- 
ed her  commercial  progress  with  a 
mildew  that  would  fetter,  if  not  endan- 
ger, American  genius  ;  and  we  unhesi- 
tatingly say,  that  America  must  take 
the  van  in  steam  as  well  as  in  other 
ships  ;  and  not  only  so,  if  steam-ships 
are  to  be  the  commercial  watch-word, 
they  must  attain  a   greater  degree  of 


MARINE    AND    NAVAL    ARCHITECTURE 


341 


speed  than  they  have  ever  yet  attain- 
ed— the  Atlantic  must  be  crossed  in 
eight  instead  of  ten  and  a  half  days, 
and  this  as  the  general  average.  Let 
not  our  readers  be  startled  at  this  an- 
nouncement, it  can  and  will  be  done, 
and  even  more,  if  steam-ships  continue 
to  carry  the  mail  and  passengers 
between  New- York  and  Liverpool. 
Steam-ships  must  advance  in  speed  as 
well  as  other  ships.  The  Californias 
have  opened  a  trade  for  fast  sailing 
ships,  that  will  in  a  few  years  astonish 
the  most  sanguine  in  relation  to  the 
speed  of  sailing  ships  ;  already  are  ships 
being  built  for  this  trade  from  200  to 
220  feet  long,  and  other  dimensions  in 
proportion.  By  the  aid  of  these  fast 
sailing  ships,  merchants  and  specula- 
tors can  obtain  the  returns  of  cargoes 
bought  on  time  before  their  notes  be- 
come due  ;  thus  we  discover  the  spirit 
of  American  movements  in  commerce 
is  onward,  and  if  steam-ships  do  not 
advance,  sailing  ships  will. 

It  is  not  only  important,  in  calcula- 
ting for  a  steam-ship.,  that  we  should 
have  a  determinate  line  of  flotation, 
but  we  should  know  the  amount  of 
displacement  below  this  line  of  immer- 
sion ;  and  more  than  this,  we  should 
locate  the  centre  of  gravity  of  this  en- 
tire bulk  of  the  immersed  part,  and  we 
should  also  know  where  to  locate  the 
centre  of  weight,  in  order  that  the  ship 


may  have  her  proper  trim,  without  be- 
ing compelled  to  carry  coal  where  we 
do  not  want  it  for  the  purpose  of  trim- 
ing  the  ship,  as  is  not  unfrequently 
the  case.  This  is  rendered  necessary  in 
consequence  of  the  bow  having  less 
displacement  than  the  after  end  ;  this 
would  seem  like  placing  the  wrong 
end  ahead  ;  but  such  is  the  fact,  that 
for  high  speed  the  bow  will  require  less 
buoyancy  than  the  stern.  If  we  divide 
the  length  on  load-line  into  two  equal 
parts,  the  consequence  will  be,  that  the 
sship  would  set  by  the  head  when 
launched,  and  if  the  centre  of  the 
weight  of  the  engine  were  located  at 
the  centre  of  buoyancy,  the  ship  would 
continue  to  be  by  the  head  ;  her  trim 
would  not  be  altered.  This  will  become 
apparent  if  we  will  but  reflect  that  the 
bow,  being  thelongest,consequent  upon 
its  being  the  sharpest,  balances  at  a 
line  of  immersion  equivalent  to  its 
weight ;  the  stern,  being  fuller,  requires 
to  be  less  immersed  than  the  bow,  to 
equilibriate ;  hence  Ave  discover  that 
if  the  engine  were  equally  divided,  and 
the  one  half  placed  on  the  centre  of 
gravity  of  the  bow,  and  the  other  on 
the  centre  of  gravity  of  the  stern,  the 
bow  would  settle  down  faster  than  the 
stern  ;  and,  as  a  consequence,  if  the 
centre  of  the  weight  of  the  engine  were 
to  be  placed  at  the  centre  of  buoyancy, 
the  effect  would   be  the  same,  though 


342 


MARINE    AND    NAVAL    ARCHITECTURE. 


aft  of  the  centre  of  length,  hence  we  dis- 
cover that  something  more  is  required. 
The  discrepancy  lies  here  ;  the  amount 
of  buoyancy  between  the  centre  of 
gravity  of  displacement  and  the  cen- 
tre of  length  should  be  determined,  and 
an  equal  amount  aft  of  the  centre  of 
gravity  of  displacement  should  be  also 
determined,  and  upon  the  margin  of 
this  bulk  should  be  the  point  longitu- 
dinally at  which  the  centre  of  weight 
should  be  located  ;  that  is  to  say,  sup- 
pose there  were  600  cubic  feet  of  buoy- 
ancy between  the  centre  of  length  rAi 
the  load-line  and  the  centre  of  the  en- 
tire displacement,  and  that  the  distance 
between  those  points  were  13  inches 
between  the  two  centres,  is  it  not  plain 
that  600  cubic  feet  of  buoyancy  must 
be  obtained  from  that  portion  aft  of 
the  centre  of  buoyancy  ?  but  it  does 
not  follow  that  the  distances  will  be 
equal  in  which  it  is  obtained  ;  that  is 
to  say,  it  may  be  found,  as  most  likely 
it  would  be,  before  we  went  as  far  aft 
as  13  inches,  but  at  whatever  distance 
we  found  the  600  cubic  feet  at,  the 
after  boundary  would  be  the  place  for 
the  centre  of  the  weight  of  the  engine. 
In  the  Plates  showing  the  lines  of  the 
ocean  steamer,  it  will  be  seen  that  al- 
though the  ®  frame  is  in  the  centre 
longitudinally,  yet  the  centre  of  buoy- 
ancy is  4i  feet  forward  of  the  longitu- 
dinal   centre  ;    as  a    consequence,  the 


location  of  the  centre  of  weight  would 
require  to  be  placed  still  farther  for- 
ward, in  order  to  prevent  the  ship's 
trimming  by  the  stern.  In  this  case  the 
steamer  is  small,  and  consequently  has 
not  sufficient  length  to  enable  us  to 
make  her  as  sharp  as  if  she  were 
larger,  and,  as  a  consequence,  longer. 
Hence  we  discover  that  it  does  not 
follow,  that  in  adding  length  to  steam- 
ships, it  must  of  necessity  be  equally 
divided  on  the  ends ;  it  often  occurs 
that  the  stern  is  sharp  enough  for  a 
speed  of  20  miles  per  hour,  while  the 
bow  can  only  be  driven  12  to  14  ;  this 
has  been  proven  on  our  river  boats  in 
not  a  few  instances.  Hence  we  say, 
that  if  speed  is  required  in  ocean  steam- 
ships, give  them  length.  Suppose  40 
feet  were  added  to  the  bow  of  the 
steamer  shown  in  Plate  2,  and  10  feet 
to  the  stern,  and  the  assumed  propor- 
tionate power  were  doubled,  may  it  not 
be  clearly  inferred  that  her  speed  would 
be  greatly  increased  ?  and  we  hesitate 
not  to  say,  that  such  vessel  could  go 
to  Liverpool  within  8  days  instead  of 
10V,  as  we  now  do.  But  an  objection 
may  be  raised  to  her  want  of  depth, 
and,  as  a  consequence,  a  want  of  suf- 
ficient strength.  If  this  supposed  want 
of  depth  were,  absolutely  necessary  for 
strength,  it  would  be  a  tenable  position; 
but  inasmuch  as  the  required  strength 
can    be   furnished   without  our    being 


MARINE  AND  NAVAL  ARCHITECTURE. 


343 


burdened  with  extra  depth,  we  would 
add,  that  she  has  a  proportionate 
amount  ;  and  it  is  presumable  that  the 
addition  assumed  would  be  sufficiently 
buoyant  to  carry  its  own  weight,  and, 
doubtless,  something  more  ;  conse- 
quently, the  draught  of  water  would 
call  for  no  more  depth  of  hold,  and  any 
extra  top  hamper  would  only  serve  to 
make  the  ship  roll.  We  have  not 
taken  the  position  of  assuming  that  the 
lines  of  the  steamer  shown  in  this  work 
was  not  sharp  enough  ;  we  only  say, 
that  if  a  greater  speed  is  required,  she 
would  be  too  small.  Without  doubt 
she  is  sharper  than  any  vessel  of  her 
class  now  built,  and  for  her  size  is  per- 
haps about  sharp  enough ;  she  could 
not,  however,  be  made  much  sharper 
without  increasing  the  length.  With 
regard  to  the  strength  of  ocean  steam- 
ships, they  cannot  be  made  too  strong. 
Of  the  manner  now  almost  universally 
adopted  of  cross-plating  the  frame  on 
the  inside,  too  much  can  scarcely  be 
said  in  its  favor.  Some,  however,  have 
supposed  that  the  single  plate  was 
enough — that  there  was  danger  of  a 
collapse  by  adding  the  cross-plate,  even 
though  they  were  rivetted  together  at 
the  crossings — those  apprehensive  fears 
are  groundless  ;  the  strength  depends 
somewhat  upon  the  size  of  the  plates, 
and  their  number  plates, one  inch  thick 
by  5  inches  wide,  is  quite  light  enough 


for  a  steamer  of  any  considerable  size. 
The  first  course  is  usually  let  into  the 
frame  at  an  angle,  with  a  vertical  posi- 
tion of  the  frame  of  45  degrees,  and 
the  second  course  runs  in  the  opposite 
direction,  at  the  same  angle — all  being1 
sufficiently  bolted  to  the  frame,  and 
rivetted  together  at  the  crossing, (which 
must  come  in  the  room  between  the 
timbers,)  renders  the  whole  fabric  strong 
longitudinally.  The  most  ready  man- 
ner of  obtaining  the  marks  for  the 
holes,  is  to  take  a  rule  staff  about  the 
width  of  the  plates,  and  bend  it  out  to 
the  place  where  the  plate  belongs,  and 
mark  the  holes  upon  it,  transferring 
the  same  to  the  plate.  But  there  are 
other  and  additional  means  by  which 
strength  may  be  added  to  steam-ships  ; 
they  may  have  iron  clamps,  which 
would  be  both  stronger  and  lighter  than 
the  same  of  wood.  We  may  also  have 
iron  keelsons  made  of  sheets  of  boiler 
iron,  bolted  on  the  sides  of  the  centre 
keelson,  which  would  take  no  room 
worth  speaking  of,  and  could  easily 
be  prevented  from  corrosion  and  rot, 
consequent  upon  the  action  of  heat 
and  salt  to  which  they  would  be  ex- 
posed ;  and  as  far  as  speed  and  strength 
are  entitled  to  notice  only,  an  iron 
steam-ship  could  be  made  both  stronger 
and  yet  lighter,  assuming  two  vessels  to 
be  built  by  the  same  model,  the  one  of 
iron  and  the  other  of  wood  ;   hence  we 


344 


MARINE   AND    NAVAL    ARCHITECTURE 


saj,  for  speed  iron  is  preferable  to 
wood.  The  corrosive  qualities,  as  we 
have  before  said,  is  a  barrier  against 
its  use  for  the  outside  shell,  but  may 
be  used  inside,  as  we  have  described, 
with  great  advantage. 

With  regard  to  the  power  of  steam- 
ships, we  deem  it  important  that  we 
should  make  some  remarks.  Many 
persons  have  supposed  that  if  the  ves- 
sel were  made  sharper,  less  power 
would  answer  all  purposes.  This  is  a 
great  mistake ;  it  is  the  place,  and  the 
only  place,  where  its  advantages  may 
be  seen.  A  large  amount  of  power  ap- 
plied on  a  full  vessel  is  thrown  away. 
True,  it  causes  the  ship  to  make  much 
disturbance ;  it  causes  an  amount  of 
resistance  equal  to  the  power  of  the 
engine,  but  this  is  not  speed.  We  might 
rend  the  vessel  into  fragments  with  the 
power  applied,  and  she  would  not  be 
fast ;  she  has  a  column  of  water  to 
raise  in  length  equal  to  the  length  of 
the  voyage,  and  in  breadth  equal  to  the 
breadth  of  the  wave  her  fullness 
generates,  and  its  depth  is  equal  to 
the  altitude  of  the  wave.  Now  it 
must  appear  quite  clear,  that  inasmuch 
as  resistance  increases  so  much  faster 
than  power  when  an  attempt  is  made 
to  increase  the  speed  of  vessels,  whether 
by  steam  or  sail,  that  it  were  a  fruit- 
less task  to  endeavor  to  remove  this 
column    of  water  fast ;  thus  we  say, 


power  is  thrown  away  on  full  vessels, 
beyond  that  which  is  required  for  a 
speed  adapted  to,  or  commensurate 
with,  the  shape  ;  and  if  a  man  is  so  un- 
fortunate as  to  own  a  full  steamer,  he 
should  be  content  with  moderate  speed, 
or  he  may  be  compelled  to  abide  by 
the  results  we  have  shown,  after  hav- 
ing spent  much  money  to  reverse  it. 
And  when  we  have  a  sharp  steamer, the 
power  is  required  to  bring  her  fully 
up  to  an  amount  of  resistance  com- 
mensurate with  the  shape,  inasmuch 
as  it  is  assumed  that  this  vessel  is 
meeting  the  resistance  on  the  sides  of 
the  bow  and  not  at  its  commencement ; 
hence  it  is  quite  manifest  that  the  ap- 
plication of  power  must  increase  the 
speed  in  a  greater  ratio  on  the  sharp 
vessel  than  on  the  full  one,  from  this 
fact,  that  the  steamboat  of  10  miles 
per  hour  makes  more  disturbance  than 
the  boat  of  20  miles  per  hour.  We 
seem,  however,  to  forget,  that  inas- 
much as  the  resistance  is  less  on  the 
sharp  vessel,  it  should  be  greater  at 
the  wheel  to  be  equal  to  the  vessel  of 
more  moderate  speed  ;  and  that  as  the 
ocean  steamer  must  have  a  very  con- 
siderable dip,  (else  the  wheel  will  be 
out  of  water  at  times,)  and  that  this  in- 
creased  dip  requires  an  enormous 
amount  of  power  to  turn  the  wheel 
sufficiently  fast  to  bring  the  ship  up  to 
her  required  resistance ;   we  make  use 


> 


MARINE    AND    NAVAL    ARCHITECTURE. 


345 


of  this  term  because  we  wish  to  be  un 
der stood  in  this  matter  to  say,  that  an 
ocean  steam-ship  (if  she  is  very  sharp) 
requiresa  considerable  amountof  resist- 
ance on  the  bow  to  keep  her  steady  ;  it 
is  like  wedging  the  bow  fast  that  it  can- 
not veer  about,  and  we  will  add,  that 
she  will  perform  better,  and  if  the  bow 
is  properly  formed,  will  prove  herself 
to  be  a  better  sea  boat  in  every  respect. 
This  leads  us  to  another  consideration  : 
the  wheel  must  be  larger,  or  must  turn 
faster ;  but  to  the  latter  there  is  this 
objection  :  the  heavy  machinery  re- 
quired for  ocean  steamers  cannot, 
without  hazard,  be  made  to  move  as 
fast  as  that  of  the  river  boats ;  hence 
we  find  ourselves  deficient  in  power ; 
and  if  we  increase  the  size  of  the 
wheel  and  secure  a  larger  dip,  we  can- 
not turn  the  wheel  fast  enough ;  and 
although  steam-ships  have  less  stroke 
than  steamboats,  they  have  cylinders 
of  much  greater  diameter,  and  require 
more  steam,  having  two  engines  ;  more 
particularly  if  they  have  reserve  power. 
Hence  we  say  that  it  amounts  to  this  : 
the  full  steamer  is  strained  by  under- 
taking to  force  her  beyond  her  appro- 
priate speed  ;  while,  on  the  other  hand, 
if  she  is  very  sharp,  and  this  sharp- 
ness is  of  the  right  kind,  it  binds  her 
together,  and  keeps  her  steady,  and  the 
ship  would  perform  better  in  every  re- 
spect by  being  driven  with  extra  or  re- 


serve power;  and  the  same  is  equally 
true  with  very  sharp  sailing  vessels 
that  have  great  length,  if  their  propel- 
ling power  is  properly  distributed. 

This  seemingly  paradox  may  be  il- 
lustrated in  the  following  manner  : 
when  a  sailing  ship  has  the  wind  di- 
rectly ahead,  she  cannot  prosecute  her 
voyage  in  its  proper  direction,  but  must 
turn  aside  until  the  wind  is  received 
partly  in  the  direction  of  the  beam, 
and  the  impulsive  power  aft  of  the 
beam,  or  at  right  angles  with  the  line 
of  direction  from  which  it  comes ; 
if  the  ship  be  full,  and  a  press  of  sail  is 
crowded  upon  her,  she  is  almost 
brought  to  a  stand  still  at  times  by  the 
power  of  the  sea  ;  the  surges  are  felt 
all  over  the  ship,  and  the  area  of  sail 
spread  may  be  increased,  but  the  ship 
will  go  no  faster  ;  she  may  labor  more, 
surge  heavier,  or  plunge  deeper,  but 
go  no  faster.  Let  this  same  ship  be 
made  sharper  by  lengthening  the  bow 
from  its  after  part  and  continuing  for 
ward  any  given  distance,  say  as  far  as 
the  front  of  the  cut-water  from  10  to 
12  feet ;  let  the  ship  be  again  placed 
in  the  same  circumstances  as  before, 
and  we  shall  find  that  she  sails  faster 
with  the  same  sails  set  as  before,  and 
that  she  makes  less  disturbance  on 
the  bow  ;  but  notwithstanding  this,  we 
shall  also  find  that  more  sail  would  be 
an  advantage  in  making  her  motions 


44 


316 


MARINE    AND    NAVAL    ARCHITECTURE. 


regular  ;  t he  vessel*  would  be  dry, 
(provided  the  bow  were  properly 
shaped,)  and  sail  faster  ;  hence  we  say, 
that  every  vessel  (and  steamers  in  par- 
ticular)  require  when  sailing  or  steam- 
ing, an  amount  of  resistance  commen- 
surate with  the  shape  ;  this  is  obtained 
by  the  application  of  power,  whether 
secured  from  the  leverage  of  the  masts 
or  the  rotary  motion  of  the  water- 
wheel  ;  and  it  may  be  set  down  as  an 
axiom,  that  under  ordinary  circum- 
stances a  diminished  resistance  on  the 
immersed  part  of  the  hull  demands  an 
increase  of  power  to  secure  the  con- 
templated speed. 

There  have  been  some  steam-ships 
built  in  the  United  States  that  have  at- 
tained a  tolerable  degree  of  speed ; 
among  these  none  stand  more  con- 
spicuous than  that  of  the  steam-ship 
Georgia — the  tables  of  which  has  found 
a  place  in  this  work.  In  contrasting 
the  advantages  of  a  proportionate 
breadth  for  steam-ships,  we  have  had 
occasion  to  notice  this  ship,  on  page 
106,  and  deem  it  only  necessary  to  add, 
that  she  has  had  less  alterations 
and  repairs  than  any  other  American 
steamer  that  has  been  built  ;  and  al- 
though she  has  her  greatest  displace- 
ment aft  of  the  longitudinal  centre  of 
length,  and,  consequently,  the  small 
end  (and  as  many  have  thought  and 
said  the   wrong  end)    ahead,  she   has 


run  1000  miles  within  60  consecutive 
hours,  which  is  equal  to  100  miles  per 
day.  This  ship,  on  her  first  voyage, 
was  trimmed  by  the  head,  under  the 
supposition  that  her  fullest  end  being 
aft,  she  would  require  to  be  by  the 
head  to  make  her  steer,  but  this 
was  found  to  be  an  error;  her  sailing 
trim  being  3  inches  by  the  stern,  and 
when  in  this  trim  there  is  no  difficulty 
in  steering  or  working  the  ship  ;  her 
mean  load-line  draught  of  water  is  16 
feet,  which  is  about  all  that  can  be 
made  available  in  running  to  New- 
Orleans,  to  which  route  she  is  remarka- 
bly well  adapted  ;  and  notwithstanding 
her  light  draught  of  water  compared 
with  her  tonnage,  which  is  equal  to 
that  of  the  largest  that  has  been  built 

in  this  country,  we  have  the  highest 
rate  of  speed  that  has  been  attained  by 
steam-ships,  with  only  about  4-5ths  of 
the  power  of  those  crossing  the  Atlan- 
tic. She  is  well  adapted  for  navigating 
one  of  the  most  dangerous  coasts  laid 
down  on  any  chart.  The  propor- 
tionate dimensions  shown  on  page  43, 
are  carried  out  in  the  construction  of 
this  ship  ;  and  if  farther  illustrations 
of  the  advantages  of  beam  were  re- 
quired, we  are  here  furnished  with 
them.  The  area  of  her  greatest  im- 
mersed transverse  section  equals  677 
square  feet;  her  launching  draught 
was  7  feet  9  inches  ;   her  constructed 


l: 


TABLES  OF  STEAMER  GEORGIA,  FINISHED  1850. 


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15 

3  5 

18 

6  0 

1 

4  0 

2  10  0 

4 

6  0 

fi 

10  0 

14 

2  4 

17 

2  5 

18    0  1 

18 

6  4 

18    7  0 

82 

7 

fi  2 

15 

fi  0 

18 

7  7 

0 

8  0 

14  0 

2 

2  0 

8 

6  0 

11 

2  0 

15 

5  1 

16    8  5 

17 

7  4 

17  10  6 

84 

7  10  4 

15 

8  4 

18 

10  0 

.... 

..  ■  . 

5 

5  0 

12 

5  1 

14    8  6 

16 

3  1 

16  11  1 

86 

15 

11   3 

19 

n  s 

.... 

10    4  4 

13 

7  0 

15     1  4 

87 

16 

0  5 

19 

1  6 

10 

10  0 

13    4  0 

Stern 

8 

0  4 

16 

2  0 

19 

3  6 

.... 

D 

n 

ii  n 

18 

5  6 

21 

11  3 

0  1( 

1    6  i 

2 

1  5 

2 

9  6 

5 

6  2 

6 

9  6 

9    2  6 

10 

6  0 

14    4  0 

F 

in 

4  1 

18  10  1 

22 

3  4 

0    5  4 

0 

10  2 

1 

3  6 

O 

7  0 

4 

10  2 

6     1  3 

8 

4  3 

12    4  4 

H 

10 

9  5 

19 

1   fi 

22 

8  2 

1 

8  0 

0 

9  2 

3  11  0 

6 

0  6 

10     1  1 

K 

19 

7  5 

23 

1  0 

0 

7  4 

1     8  7 

3 

8  7 

7    8  2 

M 

9.0 

0  4 

23 

5  4 

1 

4  7 

5    3  1 

0 

.... 

23  10  3 

.... 

2  11  2 

Stem 

ii 

1  3 

20 

2  4 

24 

3  6 

.... 

RAKE  OP   STEM  FROM  FRAME  D. 

ft.  in.  8th». 

On  first  Water  Line 2  6  0 

On  second  Water  Line 5  6  7 

On  third  Water  Line 7  2  1 

On  fourth  Water  Line 8  7  4 

On  first  Height 13  9  0 

On  second  Height 16  0  0 

On  fourth  Height 22  8  0 

OnfifthHeight 31  3  0 

5  ft.  10  in.  above  fourth  Water  Line 10  11  6 

Second  Height  is  3  ft.  above  the  first. 
Third  Height  is  2  ft.  6  in.  above  the  second. 
Second  Height  on  Slcra  is  14  ft.  4}  in. 


Second  Height  on  Stern  is  11  ft.  3  in. 

Nib  of  Stem  at  Frame  4  rises  i  in.  at  Frame  ©,  10J  in.  at  Frame  D, 
rises  2  ft.  f  in.  at  Frame  E. 

ft.    in.  sths. 

Rake  of  Stern  Post  at  fourth  Water  Line 2    3  3 

"          "        first  Height 4  11  4 

"              "          "        second  Height 7    8  5 

"              "          "        fourth  Height 12    6  5 

»              "          "        fifth  Height 14     1  6 

Heel  of  Post  aft  of  Frame  82 2    7  2 

First  Water  Line  above  Base 2    0  0 

Second"         "         "       first 3  10  0 

Third     "         "         "       second , 3  10  0 

Fourth"         "         "       third 3  10  0 

Timber  room  and  Space 2    7  0 

Frame  43  and  44—2  ft.  9  in. 


MARINE    AND    NAVAL    ARCHITECTURE 


347 


load-line  of  flotation  furnished  a 
draught  of  15  feet  6  inches  (which 
contemplates  her  without  freight) 
water,  below  which  her  displacement 
is  2700  tons    592  pounds. 

With  regard  to  steam-ships  for  speed, 
they  should  be  large;  there  is  scarce- 
ly a  limitable  length  beyond  which 
steam-ships  cannot  go,  provided  they 
combine  strength  in  proportion  to  the 
increased  size,  which  we  are  fully 
satisfied  they  may.  We  believe  there 
is  much  room  for  improvement  in  the 
marine  steam-engine  ;  likewise  in  the 
water-wheel  ;  and  while  ship-builders 
are  perfecting  the  hull,  the  engineer 
should  be  endeavoring  to  rid  the  en- 
gine of  the  enormous  amount  of  fric- 
tion, by  more  direct  application. 

Among  the  different  channels  through 
which  the  commercial  intercourse  of 
our  country  is  augmented,  the  coasting 
trade  of  the  United  States  is  not  the 
most  insignificant.  Perhaps  there  is 
no  coast  on  the  globe  of  the  same  ex- 
tent that  has  so  much  demand  for  ves- 
sels of  easy  draught  of  water.  Almost 
the  entire  southern  coast  of  the  United 
States  is  linked  to  the  ocean  by  shoal 
rivers  ;  hence  it  is  plain  that  the  ves- 
sels engaged  in  our  coasting  trade 
should  be  so  constructed  that  they  may 
be  able  to  ascend  those  rivers  to  the 
various  ports  of  entry  located  thereon. 
The  proportionate  dimensions  of  coast- 


ing vessels  will  be  found  to  differ  widely 
from  those  of  sailing  ships.  It  is  not 
unfrequently  the  case  that  schooners 
are  built  with  a  breadth  of  3  times  the 
depth;  and  we  have  known  schooners 
that  have  had  a  breadth  of  half  of  the 
length  of  keel  ;  they,  however,  had 
great  rake,  both  to  the  stem  and  stern- 
post. 

The  coasting  vessels  of  the  United 
States  combine  the  greatest  variety 
of  shape  and.  principal  dimensions; 
and  we  would  doubtless  be  quite  safe 
in  our  conclusions  were  we  to  add,  to  a 
much  greater  extent  than  in  any  other 
part  of  the  world,  which  we  think  the 
difference  in  the  draught  of  water  will 
fully  prove.  There  are  vessels  built  of 
considerable  size  that  run  on  a  draught 
of  3  feet,  and  from  this  extraordinary 
light  draught  up  to  10  feet  water  ;  they 
are  doubtless  the  most  stable  vessels  in 
the  world,  because  of  their  great 
breadth.  It  must  be  quite  apparent 
that  no  definite  instruction  can  be  given 
for  the  construction  of  coasting  vessels 
that  will  apply  universally  to  all,  inas- 
much as  some  are  built  with  a  centre- 
board, or  moveable  keel,  to  increase 
the  lateral  resistance  when  the  water 
is  of  sufficient  depth  to  admit  of  its 
being  lowered,  while  others  have  a  deep 
keel;  and  again  on  the  other  hand, 
some  have  no  centre-board  and  a  very 
small  keel  ;  and  ulthough   very  many 


648 


MARINE    AND    NAVAL    ARCHITECTURE. 


persons  are  firm  in  the  belief  that  a 
vessel  must  have  a  sharp  floor  verti- 
cally, in  order  that  she  may  sail  fast, 
yet  we  sometimes  see  a  vessel  that  is 
perfectly  flat  having  a  centre-board, 
and  sailing  faster  than  another  vessel 
having  a  very  considerable  vertical 
rise  ;  hence  we  are  brought  to  this 
conclusion,  that  it  is  in  the  shape  more 
than  in  the  vertical  rise  that  proper- 
ties of  speed  consist.  This,  however, 
is  quite  conclusive,  that  the  shape 
must  be  to  a  very  great  extent  conse- 
quent upon  the  draught  of  water,  in- 
asmuch as  the  fact  is  too  palpably 
plain  to  be  for  a  moment  questioned, 
that  where  the  draught  is  very  light, 
or  even  moderately  so,  the  bow  must 
not  be  sharp  longitudinally,  else  we 
shall  doubly  fail  in  accomplishing  our 
object ;  first,  we  shall  draw  too  much 
water,  and  in  the  next  place  we  shall 
have  an  unprofitable  vessel.  While 
we  are  desirous  to  secure  speed,  it  must 
not  be  at  the  expense  of  cargo  to  any 
very  great  extent,  inasmuch  as  the 
most  profitable  vessels  are  those  which 
carry  the  greatest  number  of  tons  or 
barrels  in  proportion  to  their  tonnage, 
and  also  carry  them  in  the  shortest 
possible  time,  and  with  the  least  wear 
and  tear  to  the  vessel,  this  is  the  great 
and  most  desirable  object  in  coasting 
vessels. 

The  tables  on  page  349  represent  a 


vessel  adapted  for  the  coasting  trade, 
of  about  10  feet  draught  of  water,  that 
would  be  adapted  to  the  schooner  rig ; 
she  would  require  no  centre-board, 
having  10  degrees  rise  to  her  floor,  and 
having  a  very  considerable  length  of 
104  feet  on  load-line,  with  26  feet  of 
moulded  breadth,  and  the  greatest 
transverse  section  in  the  longitudinal 
centre  of  length;  the  lines  being  easy, 
consequent  upon  their  unusual  length, 
would  render  her  a  profitable  as  well 
as  a  fast  sailing  vessel,  and  well  adapt- 
ed to  the  coasting  trade,  where  that 
draught  of  water  may  be  had  ;  she  may 
be  very  properly  termed  a  high-decked 
vessel,  inasmuch  as  she  is  deeper  than 
the  proportions  of  a  low-decked  vessel 
would  require.  We  mean  by  the  de- 
nominations of  high  and  low  deck,  a 
certain  adaptation  that  low-decked  ves- 
sels have  for  carrying  a  deck-load  of  such 
articles  as  are  not  perishable,  they  are 
shoaler  than  high-decked  vessels,  and 
the  scantling  or  moulding  size  of  their 
stanchions  are  generally  larger,  as  also 
their  deck-frame  ;  they  are  principally 
built  for  and  engaged  in  the  lumber 
trade,  and  not  unfrequently  carry 
from  one-half  to  five-eighths  of  their 
cargo  on  deck.  Almost  the  whole 
amount  of  yellow  pine  timber  brought 
from  the  south  is  carried  in  this  kind 
of  vessel ;  the  timber  that  is  in  the  lo« 
and  of  any  considerable  length,  say  oo 


■It 


349 


TABLES    OF    SCHOONER. 

DIMENSIONS — Length,  105  feet ;  Breadth,  26  feet ;  Depth,  from  Base  line  to  lower  side  of  Plank  sheer,  10  ft.  3-j-  in. 


i 

f-        * 

X 

H          S 

x      S 

x      a 

£        - 

X         z 

3         3 

x      e 

h 

fr"     •? 

H         — 

E»         •« 

fr-         - 

H        — 

a       ■) 

2      iJ 

a       >5 

9      J 

a       A 

a       J 

a       >3 

< 

a 

S 

a  S  » 

x  >  u 

X     >     4, 

3      •. 

eg     f"     « 

u        u 

S       u 

a  *   " 

< 

w 
a. 

< 

5 

h  3  3 

S3* 

»  <  3 

»  «  ? 

«  <  5 

n  •*  « 

»  "   s 

H 

A 

h 

en        ^ 

ts        ? 

CO            - 

-      > 

X        >S 

5     £ 

S     5 

to 

a 

< 

IB 

l-n 

H 

<* 

l» 

< 

feet. 

feet 

feet. 

feet. 

feet. 

feet. 

feet. 

feet. 

feet 

Stem 

3.94 

6.06 

b 

3.58 

5.75 

.7 

1.07 

1,5 

2.24 

3. 

6.42 

8.7 

Y 

3.06 

5.31 

2.66 

4.08 

6.5 

6.92 

8.42 

10.68 

11.79 

U 

2.62 

4.96 

4.96 

7.1 

8.84 

10.17 

11.11 

12.10 

12.58 

Q 

2.26 

4.4 

6.75 

9.31 

10.79 

11.75 

12.27 

12.74 

12.79 

M 

1.98 

4.37 

8.46 

10.8 

12. 

12.62 

12.92 

12.77 

12.83 

H 

1.7 

4.17 

9.5 

11.79 

12.72 

13.02 

13.08 

13.07 

12.75 

D 

1.52 

4.05 

10.07 

12.25 

12.98 

13.18 

13.19 

13.04 

12.66 

® 

1.46 

3.92 

10.23 

12.42 

12.99 

13.17 

13.17 

13. 

12.5 

4 

1.43 

3.79 

9.87 

12.17 

12.77 

12.99 

13. 

12.91 

12.31 

8 

1.46 

3.83 

9. 

11.5 

12.3 

12.62 

12.66 

12.68 

12.06 

12 

1.53 

3.96 

7.56 

10.33 

11.58 

12.07 

12.25 

12.28 

11.74 

16 

1.66 

4.05 

5.79 

8.58 

10.33 

11.28 

11.74 

11.75 

11.37 

20 

1.83 

4.12 

'   3.92 

6.27 

8.42 

9.99 

10.85 

11.1 

10.92 

24 

2.07 

4.31 

2.14 

3.66 

5.48 

7.54 

9.33 

10.35 

10.31 

28 

2.23 

4.56 

.78 

1.17 

1.69 

2.52 

4.42 

9.06 

9.55 

Stern 

2.33 

4.85 

.... 

•. 

.... 

.... 

7.92 

8.87 

RAKE   OF    STEM   FROM   FRAME   b. 

feet. 

On  first  Water  Line 1.08 

On  second  Water  Line 1.87 

On  third  Water  Line 2.4 

On  fourth  Water  Line 2.75 

On  fifth  Water  Line 3.11 

On  first  Height 4.16 

On  Rail 5. 

Rise  of  Stem  at  Frame  b 71 

Floor  straight — 8  feet  out  from  centre. 


RAKE  OF  POST  AFT  OF  28. 

feet 

On  Base 2.75 

On  fifth  Water  Line 3.04 

On  first  Height  at  centre 4.33 

On  Rail  at  centre 6. 

Cross  Seam  above  fifth  Water  Line 1.25 

Frames  apart 1.75 

Water  Lines  apart 1 .76 

Dead  Rise,  10  degrees. 


350 


TABLE3    OF    PILOT-BOAT    MARY    TAYLOR. 


H'GHT  OF  GUNWALL 

ABOVE 

the  Water  Line. 


Frames.  Feet. 

Stem 2.96 

2 2.54 

4 2.08 

6 1.77 

8 1.5 

12 1.04 

10 81 

20 75 

21 79 

28 96 

32 1.29 

36 1.83 

Post 1.96 

Stern 3.25 


HALF  BREADTH 
AT 

Gunwale* 


Frames.  Feet. 

2 2.21 

i. ...  3i83 

6 5.25 

8 6.33 

12 7.66 

16 8.29 

20 8.46 

21 8.29 

28 7.87 

32 7.29 

36 6.5 

Post 6.29 


HALF  BREADTH 

AT 

1st  Water  Line. 


Frames.  Feet. 

2 

4 27 

6 69 

8 1.29 

10 2.03 

12 2.83 

14 3.60 

16 4.31 

18 4.89 

20 5.25 

22 5.36 

24 5.25 

26 4.78 

28 4.00 

30 3.06 

82, 1.86 

34 9 

36 4 

Post 29 


HALF  BREADTH 

AT 

2d  Water  Line, 


Frames.  Feet. 

2 35 

4 1.02 

6 1.90 

8 2.92 

10 4. 

12 5.1 

14 6.1 

16 6.95 

18 7.53 

20 7.83 

22 7.87 

24 7.66 

26 7.11 

28 6.29 

;n 5.11 

32 3.5 

34 1.73 

36 46 

Post 29 


HALF  BREADTH 

AT 

3d  Water  Line, 


*N 


HALF  BREADTH 
AT 

4»h  Water  Line. 


Frames. 


Feet. 


2 79 

4 1.87 

6 3.17 

8 4.52 

10 5.89 


12.... 

14... 
16... 
18..., 
20... 
22 ...  . 
24 ... . 
26... 
28..., 
30..., 

32 5.96 

34 377 

36 79 

Post 29 


7.04 
7.93 
8.48 
8.75 
8.83 
8.76 
8.62 
8.42 
8.05 
7.28 


4.. 

6.. 

8.. 
10.. 
12.. 
11.. 
16.. 
18.. 
20.. 
22. . 
24 .' . 
26.. 
28.. 
30.. 
32.. 
34  . . 
36.. 
Post. 


Feet. 
1.25 
273 
4.29 
5.77 
6.97 
7.78 
8.25 
8.58 
8.76 
8.81 
8.75 
8.62 
8.46 
8.28 
8.04 
7.64 
6.87 
4.57 
2.58 


Frames. 


RISE  OF  MARGIN 
LINE 

ABOVE 

Base. 


Feet. 


Stem 6.65 

..  5.64 

..  4.63 

..  3.94 

..  3.5 

..  3.1 

..  2.84 

..  2.58 

..  2.33 

..  2.1 

..  1.86 

..  1.66 

..  1.43 

..  1.21 

..  1. 
..     .8 
..     .56 
..     .45 
..     .16 


4. 

6. 

8. 
10. 
12. 
14. 
16. 
18. 
20. 
22. 
24. 
26. 
28. 
30. 
32. 
34! 
36. 


RAKE  OF   STEM  FROM  FRAME  2. 

feet 

At  Gunwale 3.33 

At  fourth  Water  Line 3.33 

At  third  Water  Line 2.77 

At  second  Water  Line 1.16 

HEIGHT   OF  WATER  LINE  ABOVE  BASE. 

First  Water  Line  at  Post 4.42 

First  Water  Line  at  Stem 4.65 

Second  Water  Line  at  Post 5.90 

Second  Water  Line  at  Stem 6.25 

Third  Water  Line  at  Post 7.35 

Third  Water  Line  at  Stem 7.79 


feet. 
Timbering  Room 1.75 

Stern  aft  of  Frame  36 4.00 

MOULDED   SIZE  OF  STEM  AND  KEEL. 

At  Stem-head 7 

At  Frame  1 1.17 

At  Frame  7  1.46 

At  Frame  21  2. 

At  Frame  24 2. 

At  Frame  36 2. 


•-* 


^ 


MARINE    AND    NAVAL    ARCHITECTURE. 


351 


to  75  feet,  is  carried  on  deck,  while  the 
shorter  lengths  are  taken  in  the  hold 
through  a  lumber  port  cut  through  the 
bow  immediately  below  the  deck  ;  this 
class  of  vessels  are  built  principally  in 
the  New-England  States,  and  although 
they  are  profitable,  and  seem  to  answer 
the  object  for  which  they  are  built,  yet 
they  have  at  least  one  prominent  de- 
fect— being  too  low  on  the  bow ;  the 
deck  forward  should  be  high  enough 
to  allow  the  port  to  remain  above  water, 
until  the  hold  is  entirely  full.  It  is  not 
mi  frequently  the  case,  that  after  re- 
moving anchors,  cables,  &c,  on  the 
quarter  deck  to  keep  the  port  above 
water,  it  is  found  necessary  to  close  it 
before  the  hold  is  full  ;  the  conse- 
quence is,  the  deck  must  carry  the  re- 
mainder, even  though  it  be  the  largest 
half;  hence  one  of  the  reasons  why 
they  are  sometimes  wrecked. 

The  famous  Baltimore  Clipper,  of 
which  so  many  legends  have  been 
written,  the  canvas  of  which  has 
whitened  every  sea,  has  no  longer  a 
charm  among  the  owners  of  coasting 
vessels  ;  the  competition  in  the  coast- 
ing trade  renders  a  more  profitable 
vessel  desirable,  inasmuel^&'tkey  car- 
ry a  proportionately  •small  amount  of 
cargo,  and  do  not  sail  as  much  faster 
than  other  vessels  as  would  make  up 
the  defect  ;  another  reason  for  their 
gradual  disuse  is  found  in  the  fact,  that 


the  slave  trade  on  the  coast  of  Africa 
is  not  as  prolific  as  formerly,  and  their 
great  draught  of  water  shuts  them  off 
from  their  own  coasting  trade  ;  hence 
we  at  once  discover  that  vessels  drawing 
less  water,  sailing  equally  as  fast,  and 
carrying  from  30  to  50  per  cent,  more 
in  proportion  to  their  tonnage,  are 
much  better  vessels  for  the  coasting 
trade  of  the  United  States.  The  ta- 
bles we  have  referred  to  would  fur- 
nish a  vessel  of  this  description. 

It  should  not  be  forgotten  that  the 
tonnage  laws  have  no  warping  influ- 
ence on  this  class  of  vessels;  there  is 
nothing  to  be  gained  by  disproportion- 
ate principal  dimensions,  as  the  laws 
for  determining  the  tonnage  of  vessels 
having  but  one  deck,  measure  the 
depth  of  the  vessel,  and  not  assume 
her  depth  to  be  about  what  it  ought 
to  be,  regardless  of  what  it  is. 

The  centre-board,  or  centre;  slide- 
keel  to  which  we  have  alluded,  has 
proved  itself  to  be  of  great  advantage 
to  vessels  of  light  draught,  inasmuch 
as  they  are  sometimes  in  deep  water, 
when  it  can  be  lowered  or  dropped 
down  to  enable  the  vessel  to  hold  a 
better  wind,  or  to  sail  by  the  wind  with 
less  lee  way.  The  slide  keel  is  usually 
placed  above  the  middle  of  the  vessel 
longitudinally,  and  varies  in  length  ac- 
cording to  the  size  of  the  vessel,  from 
15  to  20  feet  long  ;   the  trunk  or  well 


352 


MARINE   AND    NAVAL    ARCHITECTURE. 


that  contains  and  protects  the  board, 
and  at  the  same  time  keeps  the  water 
out  of  the  vessel's  hold,  is  usually  cut 
through  the  vessel  at  the  side  of  the 
keel ;  the  smaller  sized  craft  have  the 
trunk  through  the  middle  of  the  keel ; 
it  is  framed  by  placing  a  stanchion  at 
each  end  of  the  trunk,  which  extends 
quite  through  the  frames,  and  as  high 
as  the  top  of  the  deck  ;  the  size  must 
be  sufficient  in  the  transverse  direction 
to  form  the  opening  for  the  board,  but 
to  this  may  be  added  the  thickness  of 
the  plank  with  which  the  trunk  is 
to  be  planked  on  both  sides ;  in  the 
fore  and  aft  direction,  the  stanchion 
should  be  large  enough  to  receive  all 
the  fastening  the  trunk  will  require  ; 
the  frames  which  are  thus  cut  off,  box 
into  a  piece  of  timber  placed  along 
side  of  the  keel,  and  extending  below 
far  enough  to  come  flush  with  the  bot- 
tom plank,  and  above  high  enough  to 
bring  the  first  seam  of  the  trunk  above 
the  ceiling  ;  the  length  of  this  side  keel 
should  be  sufficient  to  cover  several  of 
the  frames,  both  forward  and  aft  of  the 
trunk  ;  thus  it  will  be  perceived  that 
there  is  no  seam  in  the  well  of  the  trunk 
that  cannot  be  readily  caulked ;  this 
job  should  be  well  done,  inasmuch  as 
this  kind  of  vessel  has  suffered  severely 
in  their  reputation  in  consequence  of 
leaky  trunks.  It  cannot  be  denied 
that    they   are  less  strong  than   other 


vessels  that  have  their  frames  entire ; 
but  if  proper  care  is  taken,  and  the 
short  frames  properly  secured  by  an 
extra  side  keelson  and  knee'd  to  the 
trunk,  they  are  sufficiently  strong  for 
navigating  our  rivers,  and  in  some 
cases  our  sea-board,  where  many  are 
now  engaged.  The  board  is  usually 
hung  by  a  single  bolt  at  the  forward 
end,  about  !  of  the  breadth  of  the 
board  from  the  lower  edge,  and  at  such 
distance  from  the  forward  end  as  to 
admit  of  the  exposure  of  I  of  the  board 
below  the  bottom  of  the  keel ;  being 
thus  hung,  it  will  be  perceived  that 
when  the  edge  of  the  board  strikes  the 
bottom  of  the  river  in  shoal  water,  it 
will  rise  without  damage  to  the  vessel  ; 
and  having  a  small  chain  appended  to 
the  upper  edge  of  the  board  at  the 
after  end,  it  is  readily  raised  by  a  small 
winch  placed  on  deck  at  the  after  end 
of  the  trunk  for  that  purpose. 

It  must  be  quite  apparent,  even  to 
the  casual  observer,  that  with  a  large 
lever  extending  quite  through  the  ves- 
sel, and  a  number  of  feet  below,  acting 
in  the  one  direction,  and  with  another 
in  the  masts,  extending  many  feet 
above  the  deck,  acting  in  the  opposite 
direction,  must  have  a'tery  powerful 
tendency  to  divide  the  vessel  into  two 
parts;  hence  we  say,  that  extraordi- 
nary means  are  required  to  secure  the 
vessel  against  this  dividing  tendency  ; 


MARINE    AND    NAVAL    ARCHITECTURE. 


353 


and  an  extra  amount  of  timber  and 
fastening  are  required  to  secure  centre- 
board vessels  from  consequent  leakage 
upon  any  neglect  in  this  particular.  In 
small  vessels  there  are  many  parts 
where  screw-bolts  should  be  used  in 
lieu  of  blunt  bolts,  or  those  that  are 
riveted  ;  the  size  of  the  bolts,  both  in 
diameter  and  length,  or  the  small 
amount  of  surface  presented  by  the  re- 
duced size  of  the  timber,  renders  it 
necessary  that  the  bolt  should  possess 
more  of  the  confining  property  than  its 
surface  on  the  sides  alone  presents  ; 
and  in  addition  to  this,  bolts  in  small 
timber  are  seldom  driven  harder  than 
it  is  found  to  be  perfectly  sate  to  drive 
screw-bolts,  and  yet  possess  all  the 
drawing  properties  peculiar  to  the 
screw.  With  regard  to  the  form  of 
the  lines  of  this  class  of  vessels,  it  has 
been  found  that  inasmuch  as  the  very 
light  draught  they  are  required  to 
draw  presents  such  formation  as  would 
divide  the  fluid  very  different  from 
another  vessel  of  heavier  draught ;  in 
this  case  the  fluid  must  be  parted  in  a 
diagonal  direction  on  the  bow,  and  the 
parallel  lines  to  that  of  flotation  require 
to  be  very  round,  with  a  very  consid- 
erable rake  to  the  margin  line  of  the 
stem  ;  thus  it  will  be  perceived  that 
the  vessel  slides  partially  over  the  fluid, 
rather  than  part  it  in  a  horizontal  di- 
rection ;    ^p  lines   aft    require  to    be 


quite  hollow  near  the  extremities,  else 
the  great  breadth  of  the  buttocks  would 
prevent  the  retiring  molecules  from 
reaching  the  rudder  before  the  strength 
of  the  current,  caused  by  the  moving 
vessel,  had  partially  subsided.  Thai  a 
vessel's  motions  under  some  circum- 
stances would  be  easier  by  having  some 
dead-rise,  there  can  be  but  little  doubt  ; 
and  we  will  add,  that  an  easier  angle 
of  resistance  may  also  be  obtained  on 
the  vessel  having  some  vertical  rise  ; 
and  all  vessels  that  are  propelled  by 
sails  having  no  centre-board,  should 
have  some  dead-rise  to  the  floor,  for 
the  following  reasons  :  the  bilge  should 
not  hang  below  the  keel,  which  it  un- 
doubtedly would  (when  the  wind  was 
not  directly  aft)  were  there  no  dead- 
rise.  If  we  have  more  than  a  suffi- 
ciency for  this,  which  should  seldom 
exceed  10  degrees  (unless  the  vessel 
be  a  yacht  or  a  pilot-boat)  where  every 
other  consideration  is  sacrificed  for  sea 
qualities,  and  in  such  case  15  degrees 
would  be  as  much  as  we  could  derive 
advantage  from.  This  fact  should  not 
be  forgotten  in  modelling  sailing  ves- 
sels, viz.,  that  by  giving  the  vessel  a 
large  amount  of  dead-rise,  we  under- 
mine the  foundation  for  carrying  sail, 
and  cause  the  vessel  to  heel  or  incline 
from  her  vertical  and  proper  position 
for  speed  more  than  she  otherwise 
would.      In  a  river  where  (with  a  head 


45 


354 


MARINE    AND    NAVAL    ARCHITECTURE. 


wind,)  the  sloop  or  schooner  with  per- 
fectly flat  bottom  and  centre-board  is 
often  found  to  outsail  the  pilot-boat, 
the  reason  will  appear  obvious :  the 
sloop  with  her  board  partially  or  entirely 
out  presents  much  greater  lateral  resist- 
ance, because  she  heels  or  inclines 
less  ;  and  farther,  the  sides  of  the  board 
are  vertical  when  the  vessel  is  upright, 
while  the  bottom  of  the  other  on  the 
lee  side  presents  a  plane  parallel,  or 
nearly  so,  to  the  surface,  and  the  keel, 
from  its  inclination,  does  much  less 
toward  holding  the  vessel  to  windward 
than  an  equal  amount  of  surface  on 
the  centre-board  does.  Hence  we  dis- 
cover that  the  sloop  is  enabled  to  carry 
a  greater  amount  of  sail,  and  at  the 
same  time  makes  less  lee  way,  and 
need  not  tack  as  often  ;  but  again,  the 
great  breadth  of  the  sloop  furnishes 
her  with  very  round  side  lines,  and 
completely  divests  her  of  the  straight 
or  partially  straight  side  that  we  have 
so  fully  deprecated  in  the  preceding 
pages  of  this  work;  those  round  lines 
incline  her  to  come  to  the  wind,  when 
the  smallest  impulse  at  the  helm  favors 
this  course.  This  inequality  of  the 
two  lines  of  flotation,  although  it  causes 
all  vessels  to  carry  a  weather  helm, 
or  compels  the  helmsman  to  keep  his 
tiller  to  windward,  is  a  bane  in  all,  and 
more  particularly  in  sea-going  vessels, 
on   account  of  the  increased  submer- 


sion caused  by  the  sea,  and  of  the  com- 
paratively straight  side-line  that  this 
class  of  vessels  usually  possesses;  in  ves- 
sels of  light  draught  it  cannot  be  avoid- 
ed,  without  the  sacrifice  of  other  equal- 
ly important  qualities.  We  have  said 
that  this  round  'side-line  enabled  the 
sloop  or  schooner  to  come  into  the 
wind  quick,  and  in  this  respect  she 
would  have  the  advantage  of  the  pilot- 
boat  or  other  vertically  sharp  vessel ; 
not  only  so,  but  by  having  more  bilge  ; 
more  side  surface  is  presented,  which 
augments  the  rotundity  we  have  ap- 
preciated for  working  quick.  But 
again,  it  may  be  said  the  flat  surface 
is  also  increased  that  has  been  repu- 
diated. To  this  we  in  reply  would  only 
say,  that  the  flat  is  increased  transverse- 
ly, but  need  not  be  longitudinally,  inas- 
much as  the  lines  of  resistance  on  the 
flat  vessel  run  more  nearly  in  the  di- 
rection of  section  lines,  while  on  the 
sharper  vessel  they  run  in  the  direction 
of  diagonal  lines  ;  they  may  each  alike 
be  divested  of  the  straight  as  soon  as 
we  fairly  get  clear  of  the  influence  of 
the  base-line;  the  transversely  flat 
bottom  we  have  shown  is  an  advantage 
for  stability. 

It  must  not  be  inferred  iWm  what 
has  been  shown  that  the  vessels  en- 
gaged in  river  navigation  are  entirely 
free  from  discrepancies  ;  but  we  feel 
quite  safe  in  the  assertion,  that  they 
»  » 


** 


. 


MARINE    AND    NAVAL    ARCHITECTURE 


359 


pierced.  A  practical  builder  would 
never  think  of  sparring- two  ships  alike, 
because  they  were  of  the  same  princi- 
pal dimensions,  without  reference  to 
the  model ;  and  yet  this  has  been  the 
stereotyped  practice  for  years  in  the 
Navies  of  both  the  Old  and  New 
World.  That  it  is  less  difficult  to  con- 
struct vessels  for  the  avowed  purposes 
of  war,  will  appear  manifest,  if  we  but 
consider  the  objects  to  be  attained  ; 
first,  the  vessel  shall  possess  the  neces- 

*  sary  quality  of  being  able  to  carry  and 
work  her  guns  in  all  weathers  ;  this 
calls  for  stability,  both  theoretical  and 
practical  ;  the  second  essential  quality 
is  found  in  the  speed  necessary  to  be 
attained,  for  a  vessel  of  war  should  be 
fully  able  to  outsail  all  other  vessels, 
particularly  those  designed  for  freight- 
ing purposes  ;  and  yet  the  fact  is  too 
palpably  plain  to  be  for  a  moment 
questioned,  that  the  navy  is  behind  the 
merchant  service  in  point  of  speed, 
notwithstanding  the  many  varying  cir- 
cumstances   to    which    the    merchant 

'  ship  is  liable,  that  the  war  vessel  does 
not  encounter.  The  merchant  ship 
must  be  built  by  such  dimensions  as 
will  enable  the  owner  to  gain  by  her 
measurement ;  she  must  carry  more 
than  her  tonnage,  and  as  much  as  other 
ships,  or  she  is  unprofitable  ;  she  must 
be  loaded  often  in  a  hurry,  and  without 
reference  to  the  moments  of  inertia ; 


and  in  addition  to  this,  the  builder - 
finds  it  absolutely  necessary  to  deceive 
the  owner  in  relation  to  the  dimen- 
sions, model  or  spars,  to  save  himself 
from  the  cruel  mortification  of  witness- 
ing in  the  ship  he  builds  a  total  failure 
in  some  of  the  most  essential  qualities, 
while  he  is  compelled  to  keep  the  im- 
provement to  himself,  and  thus  feed 
the  vanity  of  ship  owners ;  and  when 
we  remember  that  the  private  builder 
is  expected  to  (and  does)  improve 
against  this  tide  of  influences  that  op- 
pose him,  we  cannot  but  admit  that  it 
is  less  difficult  to  construct  a  war  than 
a  merchant  ship.  The  war  ship  has 
a  determinate  cargo,  the  weight  of 
which  is  known,  and,  as  a  consequence, 
the  centre  of  gravity  of  this  weight  is 
also  known,  and  the  weight  can  be  so 
distributed  as  to  furnish  the  most  ad- 
vantageous trim  for  speed.  She  is  re- 
quired to  carry  a  sufficiency  of  provi- 
sion in  addition  to  her  armament  for  a 
limited  period,  and  no  more — under 
these  favorable  circumstances,  we  see 
nothing  to  prevent  them  from  being 
the  fastest  sailing  ships  on  the  globe  ; 
but  the  contrary,  until  within  a  very 
few  years,  has  been  the  case. 

With  regard  to  requirements  neces- 
sary to  secure  the  first  essential  quality 
in  war  ships,  viz.,  stability,  we  say  that 
a  oood  degree  of  breadth  is  required, 
the    proportionate    amount    of   which 


360 


MARINE    AND    NAVAL    ARCHITECTURE. 


will,  in  sonic  degree,  depend  upon  the 
weighl  of  (he  battery  to  be  sustained  ; 
if  the  battery  be  on  more  than  one 
deck,  the  breadth  should  be  5  that 
of  the  depth;  the  length  should  be  at 
least  5  times  that  of  the  breadth,  and 
this  would  only  accord  with  the  pro- 
portion of  some  merchant  ships.  It 
must  not  be  expected  that  a  ship  can 
be  an  extraordinary  fast  sailer  without 
length.  The  day  is  not  far  distant  when 
merchant  sailing  ships  will  be  built  of 
a  length  6  times  their  breadth,  and  if 
war  vessels  are  to  sail  from  12  to  13 
knots  by  the  wind,  which  they  should 
do,  they  must  be  long.  Much  may  be 
gained  by  reducing  the  weight  they 
are  now  required  to  carry.  It  must 
be  apparent  to  the  thinking  man,  that 
it  is  much  easier  to  obtain  water  than 
other  supplies  belonging  to  the  provi- 
sionally calender  in  foreign  ports;  hence 
we  say,  that  if  it  is  necessary  to  carry 
provision  for  four  months,  it  is  not  ne- 
cessary to  carry  water  for  more  than 
2i  to  3  months;  the  amount  of  buoy- 
ancy necessary  to  sustain  this  extra 
amount  of  water  may  be  taken  off  the 
model,  and  thus  diminish  the  resistance, 
which  will  enable  the  ship  to  sail  faster, 
and,  consequently,  render  her  more  ef- 
ficient, inasmuch  as  a  war  vessel  is 
little  better  than  a  failure,  if  she 
does  not  surpass  in  speed  other  sailing 
vessels.     If  we  should  judge    of  the 


feelings  of  others  from  what  would  be 
our  own,  were  we  appointed  to  a  ship 
that  in  point  of  speed  was  destined  to 
follow  in  the  distance,  chilling  indif- 
ference would  fill  the  place  that  would, 
under  other  circumstances,  have  been 
filled  by  enthusiastic  zeal.  The  very 
form  and  nature  of  our  government 
calls  for  an  efficient  Navy,  not  formi- 
dable by  the  number  of  guns  heaped 
upon  one  vessel,  or  by  the  terrific  frown 
of  a  few  ships  of  the  line,  that  could 
be  taken  by  a  single  steamer — ships 
that  are  formidable  only  in  fine  weather 
at  sea,  or  to  a  crippled  vessel  of  the 
enemy  that  is  unable  to  maintain  her 
ordinary  speed  by  some  casualty.  The 
annals  of  the  Navies,  both  of  the  Old 
and  New  World,  will  show  how  com- 
paratively little  service  this  class  of  ves- 
sels have  rendered  ;  nor  indeed  is  it 
reasonable  to  suppose  it  could  be  other- 
wise ;  and  whatever  may  be  said  to  the 
contrary,  we  say  that  it  would  be  a 
wise  policy  for  the  United  States  to 
razee  all  her  ships  of  the  line  ;  they 
would  be  capable  of  rendering  much 
more  efficient  service  at  much  less 
cost.  The  only  reasons  that  can  be 
adduced  (having  the  least  claims  to  fea- 
sibility) why  this  measure  should  not 
be  adopted,  is  found  in  the  fact  that 
other  nations  have  not  done  so  ;  tlius  i 
giving  abundant  evidence,  that  in  naval 
operations   we    are   willing   to   follow, 


•*-.    ■? 


MARINE    AND    NAVAL    ARCHITECTURE. 


361 


while  every  other  interest  is  satisfied 
with  nothing  short  of  the  lead.  Let 
ns  turn  our  eyes  to  the  history  of  the 
Old  world,  and  see  what  have  been 
the  effects  consequent  upon  a  formi- 
dable Navy,  made  up  principally  of 
ships  of  the  line.  That  it  was  the 
principal  cause  of  the  loss  of  the  Span- 
ish Armada  of  15S8,  few  will  deny. 
We  are  told  that  from  the  year  1756 
to  1760  France  had  taken  from  Eng- 
land 2539  vessels ;  and  during  the 
same  period  England  had  captured 
from  France  944  vessels  ;  during  this 
time  she  had  120  ships  of  the  line, 
all  of  which  were  in  active  service  ; 
France  had  not  a  single  ship  of 
the  line  at  sea — a  more  conclusive 
evidence  could  scarce  be  adduced  of 
the  inefficiency  of  this  class  of  vessels, 
inasmuch  as  it  is  notorious  that  Eng- 
lish valor  was  above  suspicion,  when 
the  terms  were  equal.  Were  it  neces- 
sary, we  might  show  the  issues  of  the 
present  century,  with  the  history  of 
which  doubtless  our  readers  are  fa- 
miliar, and  need  not  be  repeated.  But 
apart  from  these,  there  are  other  rea- 
sons why  the  construction  of  ships  of 
the  line  should  be  abandoned.  We 
have  said  that  proportion  was  the  ral- 
lying watch-word  in  the  construction 
-of  ships — not  less  applicable  to  naval 
than  to  merchant  vessels.  We  find 
upon  applying  these  proportions  to  the 


ship  of  the  line,  we  cannot  secure  a 
sufficiency  of  stability,  and  at  the  same 
time  possess  all  other  desirable  quali- 
ties ;  for  example,  their  great  height 
above  water,  to  which  must  be  added 
the  weight  of  guns  above  the  several 
decks,  rendering  it  necessary  that  they 
should  have  great  breadth  ;  to  this, 
however,  there  can  be  no  objection, 
provided  it  were  not  absolutely  neces- 
sary to  carry  this  extra  breadth  to  the 
extremities,  which  incapacitates  them 
for  even  an  ordinary  amount  of  speed, 
and  renders  them  the  dullest  sailers 
that  navigate  the  ocean.  We  have  it 
from  no  less  authority  than  the  officer 
who  commanded  one  of  the  best,  if  not 
the  very  best  ship  of  the  line  belonging 
to  the  Navy  of  the  United  States,  that 
with  a  head  wind  and  sea,  she  could 
not  make  more  than  6  knots  per  hour, 
and  she  drifted  to  leeward  more  than 
any  vessel  he  ever  saw,  and  at  the  same 
time  rolled  less ;  this  is  not  the  result 
of  observation  of  a  single  day,  but  of  a 
whole  cruise  of  2  years  or  more,  and 
furnishes  abundant  evidence  that  a  full 
bow  cannot  sail  fast,  and  that  a  great 
draught  of  water  is  no  security  against 
drifting  to  leeward,  unless  the  shape 
be  adapted  to  speed  ;  but  admitting 
that  a  ship  of  the  line  could  be  so  con- 
structed as  to  make  her  a  fair  sailing 
vessel,  and  at  the  same  time  retain  all 
her  efficiency,  we  say  even  then  it  is 


46 


t 


362 


MARINE    AND    NAVAL    ARCHITECTURE. 


an  extravagant  manner  of  distributing 
force  upon  the    high   seas  ;   it   is  true, 
that    the    sight  of  a  ship  of  the    line 
moored  before  a  town  or  a  battery  of 
equal  power,  is  calculated  to  strike  dis- 
may in   the  ranks  of  the  enemy,  but 
the    chances  are    rare    in    which    the 
same  number   of  guns  placed  on  the 
decks  of  two   or   three    vessels   would 
not  accomplish  more,  even  though  all 
this   force  were  required  at  the  same 
place,    apart   from  the   fact   that    this 
force    may    be    divided,    if   necessary. 
The  argument  used  as   a  reason  why 
the  United   States  should  not  abandon 
the  construction  of  this  class  of  vessels 
is    weak  and    futile.     That  a  foreign 
government  would  treat  an  ambassador 
with  less  dignity  on  account  of  his  not 
having  been  sent  out  in  a  ship  of  the 
line,  is   without    the    slightest   founda- 
tion, or  that  the  laws  of  nations  would 
not  be  as  fully  respected,  or  could  not 
be  as  fully  enforced  by  an  equal  amount 
of  power  distributed  on  more  than  one 
vessel,  betrays  a  want  of  courage  that 
has  never  stigmatized  the  American 
name,  either  on  land  or   sea.      That  it 
is  more  honorable  to  move  at  the  slow 
pace   of  6  knots  an  hour  in   a  ship  of 
the    line,    than    to    sail    12  knots    an 
hour  under  the  same  circumstances  in 
another  ship,  is  a  logic  entirely  obsolete 
in   any   other    than    naval    operations, 
particularly  in  this  age  of  advancement. 


To  make  the  ship  of  the  line  a  fast 
sailer,  would  be  an  expensive  under- 
taking, even  if  it  could  be  accomplished 
without  hazard.  But  there  is  another 
important  fact  in  connection  with  this 
subject  that  should  not  be  brooked  in 
silence  ;  it  is  absolutely  necessary  that 
a  ship  of  the  line  should  draw  at  least 
26  feet  of  water,  (we  allude  to  those  of 
the  first  class,)  and  we  very  much 
doubt  whether  there  are  any  belonging 
to  the  Navy  of  the  United  States  that 
have  gone  to  sea  at  so  light  a  draught. 
The  height  and  weight  above  water 
require  a  sufficiency  for  stowage  below, 
to  enable  the  ship  to  maintain  the  equi- 
librium of  stability  when  a  press  of  sail 
is  spread  to  the  wind,  inasmuch  as  the 
centre  of  gravity  of  the  weight  above 
water  is  high,  the  centre  of  gravity  of 
the  weight  below  water  should  be  cor- 
respondingly low,  else  the  leverage  will 
be  small  for  carrying  sail.  With  this 
heavy  draught  of  water  the  ship  is  shut 
out  of  many  important  ports,  both  at 
home  and  abroad  ;  there  are  but  three 
or  four  ports  she  could  enter  in  the 
whole  range  of  coast  belonging  to  the 
United  States,  no  matter  what  casualty 
might  occur ;  this  objection  alone, 
were  there  no  other,  should  be  a  suffi- 
cient reason  for  abandoning  the  farther 
use  of  this  class  of  vessels. 

It   may  be  said   with   regard  to  the 
speed   of  ships  of  the   line,  that  they 


"*W 


MARINE  AND  NAVAL  ARCHITECTURE 


363 


arc  only  dull  when  on  a  wind,  or  when 
sailing  by  the  wind  ;  that  when  the 
wind  is  free  they  sail  much  better — 
this  we  admit,  and  are  willing  to  ad- 
mit another  fact,  viz.,  that  a  Chinese 
Junk,  or  a  scow,  will  sail  before  the 
wind;  the  sailing  qualities  of  ships  are 
not  determined  by  the  speed  with  which 
they  can  drift  in  the  direction  of  the 
wind,  but  by  the  excess  of  propulsion 
over  the  resistance  presented  by  the 
immersed  surface.  The  ships  of  the 
line  of  the  United  States  Navy  have  an 
excess  of  capacity  beyond  what  is 
actually  necessary  ;  they  carry  too 
much  water  for  their"  provisions.  It 
may  be  said  that  the  excess  of  water 
need  not  be  taken,  but  in  answer  to 
this  proposed  remedy,  it  may  be  only 
necessary  to  say,  that  this  would  light- 
en the  ship  above  her  determinate  line 
of  flotation,  and,  as  a  consequence,  di- 
minish her  stability  ;  the  only  remedy 
can  be  found  in  the  first  construction : 
the  proportionate  draught  of  water  is 
not  at  fault — it  is  the  shape  ;  they  are 
fuller  than  is  actually  necessary,  by 
an  amount  of  buoyancy  equal  to  this 
excess;  this  being  entirely  impractica- 
ble, it  only  remains  to  razee  or  relieve 
them  of  the  spar  deck  with  all  its  ap- 
purtenances, and  they  will  be  found  to 
be  much  more  efficient,  quite  as  for- 
midable, and  less  expensive. 

Notwithstanding   the    British   Navy 


is  at  this  time  more   efficient  and  for- 
midable than    perhaps  it  ever  was  be- 
fore, we    find  but  73  ships  of  the  line 
on  her    navy  list   for  1850,  15  only  of 
which  are  in  commission,  and   the  re- 
mainder, 58  in  nnmbcr,  are   laid  up  in 
ordinary  ;   while,  as  we  have  shown,  in 
1760  she  had  120  ships  of  the  line,  and 
all    in    commission.      If  experience    is 
worth  as  much  to  nations  as  to    indi- 
viduals, our    Government  might   learn 
something  tangible  from  this  ;    but  we 
need  not  circnm navigate  the  globe  to 
show  the  inefficiency   of  ships  of  the 
line.      A  line  preparatory  to  action  can 
be   formed  of  other   ships   than  those 
having  two  gun  decks  and  a  spar  deck, 
that   will  prove  more  powerful  in    the 
weight,  if  not  in   the  altitude  of  their 
battery.      The  dimensions  of  a  ship  of 
the  line  differs  but  little  from  the  fol- 
lowing:    207   feet    on   the    main   gun 
deck  ;   54  feet  beam  ;  and  36$  feet  from 
base-line   to   the  top  of  the  main  gun 
deck    beam ;    thus    we    find    that   her 
proportions   are  good,  when   the    spar 
deck  is  excluded  from  the  depth — hav- 
ing about  3    feet  of  breadth   for  2   of 
depth  ;   hence    we    say,  that    although 
her   shape   gives   her    stability   beyond 
the  usual  proportion,  yet  her  stability 
is  artificial,    inasmuch    as    her   arma- 
ment has  a  permanent  location,  when 
the  ship  is  in  commission.     But  enough 
has  been  furnished  upon   this  subject. 


-*., 


5k, 


364 


MARINE    AND    NAVAL    ARCHITECTURE. 


The  next  class  of  vessels  that  de- 
mands our  attention  is  that  of  the 
Frigate :  this  description  of  war  ves- 
sel exhibits  (even  to  the  casual  ob- 
server) the  constituent  properties  of 
efficiency.  The  first  conclusion  ar- 
rived at,  is  her  proportions :  her  lower 
deck  guns  are  carried  as  high  as  the 
ship  of  the  line,  and  her  length  is  seen 
to  advantage,  not  being  absorbed  in 
top  hamper,  or  surplus  height.  If  the 
past  can  furnish  an  index  for  the  fu- 
ture, we  feel  quite  safe  in  saying,  that 
until  within  a  very  few  years  the 
Frigates  of  the  Navy  of  the  United 
States  have  rendered  most  efficient 
service.  The  term  Frigate  applies  to 
a  ship  having  one  covered  gun  deck, 
and  carrying  more  than  28  guns  ;  there 
are  two  classes,  first  and  second,  and 
they  are  designated  by  the  number  of 
guns  they  carry.  Whatever  may  have 
a  direct  connection  with  the  weight  of 
provisions,  guns  and  other  equipments, 
(more  strictly  speaking)  pertains  to 
other  branches  of  the  naval  service 
than  that  of  the  construction  of  the 
hull,  inasmuch  as  the  several  depart- 
ments move  each  in  its  appropriate 
sphere  ;  notwithstanding  this,  the  con- 
structor should  know  the  amount  of 
the  entire  weight  to  be  sustained  be- 
fore he  can  design  a  draft  having  suffi- 
cient displacement  to  sustain  (not  only 
this  weight,  but)  the  additional  weight 


of  the  ship  herself;  but  this  is  not  all, 
the  constructor  should  be  entirely  free 
from  the  trammeling  influences  of  fur- 
nished dimensions  ;  it  is  only  necessary 
that  he  should  know  the  weight  of  the 
ship  with  all  on  board,  the  dimensions 
belong  properly  to  him,  and  on  him 
should  the  responsibility  rest  of  her 
performance,  or  her  ability  to  carry  and 
work  her  guns  in  all  weather  ;  our 
Government  has  been  at  fault  in  this 
particular ;  her  recent  course,  how- 
ever, has  furnished  some  indications 
of  a  disposition  to  place  the  responsi- 
bility where  it  belongs  in  relation  to 
smaller  vessels,*and  we  say  if  in  one, 
why  not  in  all? 

It  cannot  be  expected  that  the  Sec- 
retary of  the  Navy  should  know  (but 
for  a  comparatively  short  period)  the 
present  condition  of  the  Navy,  or  its 
future  wants  ;  his  immediate  connec- 
tion with  the  political  organization  of 
the  Cabinet  forbids  more  than  a  super- 
ficial knowledge  ;  hence  we  may  rea- 
sonably infer  that  he  must  have  advi- 
sory counsel  from  some  source,  and 
we  are  brought  to  the  threshold  of  an 
inquiry,  from  what  department  should 
it  emanate  ?  We  may  perhaps  be  al- 
lowed to  say,  if  the  past  can  furnish 
an  admonition  for  the  future,  let  all 
that  pertains  to  the  manner  and  form 
of  construction  emanate  from  the  me- 
chanical department  of  this  branch  of 


MARINE    AND    NAVAL    ARCHITECTURE. 


365 


the  Government.  It  has  been  justly 
remarked  by  an  eminent  ship-builder, 
that  he  who  could  not  with  his  own 
hands  make  a  model,  could  not  design 
one  ;  and  it  is  notorious,  that  while 
the  modelling  of  ships  and  other  ves- 
sels belonging  to  the  Navy  was  in  the 
hands  of  a  board  of  commissioners,  a 
downward  tendency  in  every  essential 
quality  was  but  too  plainly  manifest ; 
and  had  not  better  councils  prevailed, 
the  Navy  would  ere  this  have  been  a 
foul  blot  upon  our  national  escutcheon. 
We  are  glad  to  see  that  a  change  of! 
measures  has  effected  wonders,  and 
that  instead  of  the  miserable  failures 
that  succeeded  each  other  in  quick 
succession,  the  bureau  system  has 
wrought  a  salutary  change.  It  cannot, 
however,  be  expected,  that  even  under 
the  present  system,  the  Navy  of  the 
United  States  can  keep  pace  with  the 
improvements  of  this  wondrous  age. 
With  few  exceptions,  the  Naval  Con- 
structors receive  most  of  the  knowledge 
they  possess  of  ship-building  from  with- 
in the  walls  of  a  Navy  Yard  ;  thus 
knowledge  becomes  hereditary,  and 
the  apprentice  is  taught  that  science  is 
the  one  thing  needful,  and  that  what- 
ever emanates  from  another  channel 
is  of  little  consequence.  It  is  thus  that 
habits  are  formed,  which  are  like  bands 
of  iron  when  once  created:  and  there 
are  few  that  are  thus  circumstanced 


who  do  not  carry  the  pressure  of  these 
bands  down  to  the  loneliness  of  the 
tomb.  The  effects  of  this  course  has 
a  most  pernicious  influence  upon 
genius  when  in  the  bud  of  youth. 

Operative  mechanics  having  served 
an  apprenticeship  in  one  of  the 
Navy  Yards",  well  know  how  greatly 
they  felt  the  need  of  that  knowledge 
which  is  obtained  only  by  prnctice  ; 
the  small  amount  of  real  science  which 
they  vainly  supposed  was  to  be  the 
palladium  of  success  in  all  future  opera- 
tions, vanished  like  clew  before  the  sun, 
and  they  were  left  to  learn  in  riper  years 
the  very  first  principles  of  ship-build- 
ing. It  may  be  assumed  that  this 
is  visionary,  or  that  these  are  excep- 
tions to  the  general  rule  ;  but  we 
ourselves  have  been  taught  these  les- 
sons, and  had  we  not  laid  a  founda- 
tion among  the  private  competing  in- 
terests of  the  day,  we  should  have  been 
subject  to  the  mortifying  necessity  we 
have  described.  We  have  said  that 
science  without  practice  was  of  little 
avail,  and  practice  alone  is  also  equally 
dark;  but  blend  them  the  one  with  the 
other,  and  they  furnish  a  system  worthy 
of  the  admiration  of  the  finest  and 
most  brilliant  genius,  rising  in  organized 
proportions  like  a  new  Cythera  from 
the  enchanted  wave. 

Let  Naval  Constructors  become  di- 
vorced from  those  habits  to  which  they 


3GG 


MARINE    AND    NAVAL    ARCHITECTURE. 


have  been  so  long  wedded,  and  look  at 
the  rapid  progress  of  commercial  en- 
terprise, and  they  will  learn  that  not 
onlv  Frigates,  but  even  their  Corvettes 
and  Sloops  of  War  are  indifferent  sail- 
ing vessels  compared  with  many  in  the 
merchant  service.  Ships  no  larger 
than  Sloops  of  War  are  built  ronger  than 
Frigates  of  the  United  States  Navy, 
and,  as  we  have  shown,  ships  are  now 
building  that  are  longer  than  any  ship 
in  the  Navy,  the  Pennsylvania  not  ex- 
cepted. That  our  Frigates,  in  their 
sailing,  as  well  as  other  qualities,  are 
equal  to  any  on  the  globe,  we  have  no 
hesitation  in  adding  the  weight  of  our 
testimony  ;  but  are  they  not,  some  of 
them  at  least,  models  of  the  past  cen- 
tury ?  and  are  those  of  the  present 
century  superior  models  to  those  of 
the  last  ?  does  their  performances  prove 
them  such?  While  we  readily  admit 
that  the  Navy  of  the  United  States,  as 
far  as  the  models  of  her  ships  may 
stand  connected  with  the  operations 
of  a  Navy,  is  equal  to  any  on  the  globe, 
we  do  not  admit  that  in  this  matter 
we  should  remain  in  a  state  of  eternal 
childhood.  Inasmuch  as  American 
commercial  enterprise  surpasses  that 
of  all  other  nations,  in  like  manner  the 
American  Navy  should  be  the  most 
efficient  on  the  globe.  Unless  there  is 
a  greater  improvement  in  the  sailing 
qualities    of  the    ships  of  the   United 


States  Navy  than  there  has  been,  com- 
mercial enterprise  will  not  only  raise 
the  means  for  the  support  of  com- 
merce, but  it  will  also  build  the  ships 
that  are  to  protect  it. 

With  regard  to  other  qualities  than 
those  of  speed,  they  lack  strength, 
more  particularly  if  their  length  be  in- 
creased ;  they  should  be  plated  diago- 
nally across  the  frames  as  steamers  are. 
We  have  no  hesitancy  in  saying  that 
the  shape  of  the  greatest  transverse 
sections  are  altered  from  the  original 
mould  whenever  the  ship  is  under  a 
press  of  sail  with  the  wind  abeam;  this 
is  the  effect  of  the  weight  of  her  bat- 
tery, and  is  often  seen  in  the  opening 
of  the  water-way  seam,  where  the  di- 
vision of  strain  takes  place  at  every 
roll,  more  particularly  when  the  guns 
are  housed  with  their  muzzles  against 
the  side. 

The  most  efficient  class  of  sailing 
vessels  belonging  to  the  Navy  of  the 
United  States,  are  those  denominated 
Sloops  of  War.  This  class  of  ships 
have  within  a  few  years  undergone  an 
entire  change  ;  the  dull-sailing,  bad- 
steering,  straight  and  wall-sided,  shape- 
less hulks  that  disgraced  the  National 
Ensign,  have  occasionally  been  eon- 
verted  into  store-ships;  others  have 
been  broken  up,  and  now  few  remain  as 
engines  of  war.  Their  places  have  been 
supplied  with  others  that  answer  quite 


MARINE    AND    NAVAL    ARCHITECTURE. 


367 


well  the  object  designed  ;  there  is  yet 
much  room  for  improvement,  but  taken 
as  a  whole,  they  are  creditable  vessels. 

The  construction  of  these  vessels 
has  been  left  in  the  hands  of  the  con- 
structors themselves,  who  have  fully 
shown  the  advantages  arising  from  en- 
trusting  to  mechanics  the  management 
of  mechanical  operations.  These  ves- 
sels, with  rare  exceptions,  are  con- 
stantly in  commission  ;  the  exceptions 
are  very  generally  those  periods  in 
which  they  are  undergoing  repairs,  of 
which  they  seem  to  require  much  more 
than  ships  in  the  merchant  service. 

It  is  not  our  purpose,  nor  yet  our 
province,  to  induct  our  readers  into  the 
path  usually  followed  by  writers  on 
Naval  Architecture,  who  have  detailed 
the  manner  of  naval  construction  prac- 
tised in  the  Old  world,  and  the  many 
others  suggested  by  the  theorists  of  an 
obsolete  age.  But  believing  as  we  do, 
and  for  tangible  reasons  already  given, 
that  naval  operations  throughout  the 
world  are  very  far  behind  the  mercan- 
tile marine,  we  deem  it  only  necessary 
to  point  out  the  most  prominent  defects 
in  the  manner  of  construction,  and 
show  the  remedy.  We  have  already 
furnished  the  lines  and  tables  of  some 
of  the  finest  and  most  efficient  vessels 
on  the  globe,  and  we  have  also  de- 
scribed the  manner  of  constructing 
them  ;   hence  it  only   seems  to  us  ne- 


cessary to  give  a  general  description, 
inasmuch  as  many  of  our  merchant 
ships,  in  case  of  a  rupture  with  a  foreign 
power,  (possessing  a  very  considerable 
navy,)  could  be  converted  into  Frigates, 
Corvettes,  and  Sloops  of  War,  in  suffi- 
cient numbers  in  the  space  of  three 
months  to  render  our  Navy  the  most 
formidable  for  sailing-  vessels  on  the 
globe  ;  these  ships  are,  as  it  regards 
strength,  equal  to  any  vessels  in  the 
Navy  ;  the  enormous  cargoes  and  the 
press  of  sail  they  carry,  and  the  small 
amount  of  repairs  they  require,  incon- 
testably  prove  this.  It  may  be  said 
that  were  guns  placed  on  their  decks, 
the  case  would  be  quite  different  :  we, 
however,  think  otherwise  ;  it  matters 
not  whether  the  cargo  be  guns  or  rail- 
road iron,  and  many  of  these  ships  carry 
an  amount  between  decks  equal  to 
any  battery,  besides  the  great  bulk 
of  the  same  material  in  the  hold.  We 
will  go  farther  and  say,  that  there  is  no 
ship  in  the  Navy  that  is  able  to  do  the 
work  that  many  merchant  ships  have 
done,  and  still  retain  their  shape  with 
the  same  amount  of  repairs  ;  the  rea- 
son will  appear  obvious,  if  we  but  con- 
sider that  the  tanks  for  water,  and  the 
spaces  left  for  kentledge,  deprive  the 
ship  of  a  great  amount  of  strength,  in- 
asmuch as  most  of  the  space  occu- 
pied by  these  is  tilled  with  heavy  bilge 
strakes,  and  with  sister  keelsons  ;  these 


368 


MARINE    AND    NAVAL    ARCHITECTURE 


render  the  bottom  and  bilge  very 
strong  ;  the  top-sides  are  not  overlook- 
ed. Very  many  of  our  merchant  ships 
have  live-oak  and  locust  top-timbers 
and  stanchions  ;  and  as  it  regards  the 
manner  of  putting  the  frames  together, 
are  actually  stronger  than  those  of  the 
Navy,  inasmuch  as  the  distribution  of 
the  butts  of  the  timbers  is  more  general. 
No  one  in  a  private  yard  would  think 
of  adhering  with  any  degree  of  tenacity 
to  the  diagonal  sirmark  for  cutting  off 
the  head  or  heel  of  a  timber  ;  it  should 
be  remembered  that  the  greatest 
amount  of  strength  is  obtained  from 
an  equal  distribution  of  the  butts  ;  and 
with  regard  to  the  manner  of  fastening 
the  ships  of  the  two  classes,  we  deem 
it  rather  a  detriment  than  otherwise 
to  extend  the  fastening  of  the  deck 
frame  through  the  outside  plank,  and 
we  are  not  alone  in  this  matter.  It  is 
assumed  by  those  whose  province  it  is 
to  determine  how  much  fastening  is 
required,  in  vessels  of  war,  that  the 
plank  should  be  square  fastened  to 
the  timbers  throughout ;  this,  it  must 
be  admitted  is  enough,  and  if  enough 
in  one  part,  why  not  in  all?  Square 
fastening  implies  2  bolts,  spikes,  or 
tree -nails  in  each  timber,  or  4  in 
the  frame  in  each  plank.  It  will  not 
be  denied  that  more  than  a  suffi- 
ciency is  an  injury;  in  this  case  it 
is  an  injury  in  two  respects  :    first  it 


weakens  the  plank,  and  secondly  it 
causes  the  timber  to  rot  sooner  than  it 
would  otherwise  do  ;  and  most  surely 
no  one  will  say  that  the  head  of  the 
bolt  would  not  rest  quite  as  firm  on  a 
live-oak  top-timber  as  on  a  white  oak 
plank;  and  this  extension  and  expo- 
sure of  the  deck  fastening  through  the 
outside  plank,  is  one  of  the  reasons 
why  the  ships  of  the  Navy  rot  so  much 
sooner  than  merchant  ships,  in  con- 
nection with  another,  viz.,  that  of  a 
want  of  proper  ventilation.  It  is  no- 
torious, that  our  ships  of  war,  although 
built  of  what  is  assumed  to  be  the  best 
material,  rot  in  a  very  few  years ;  in 
some  instances  on  particular  stations 
a  single  cruise  of  3  years  was  sufficient 
to  warrant  a  new  suit  of  wales.  There 
is  much  greater  pains  taken  to  venti- 
late merchant  ships  than  ships  of  war, 
in  addition  to  the  natural  advantages 
arising  from  the  frequent  discharge  of 
cargo.  We  are  glad  to  learn  that  the 
Navy  department  have  adopted  mea- 
sures to  determine  the  best  or  proper 
time  for  cutting  timber,  and  the  best 
mode  of  curing  it,  or  securing  it  against 
dry  rot  ;  in  connection  with  this,  their 
investigations  also  combine  a  deter- 
mination  of  the  specific  gravity.  Those 
experiments  are  confined  to  the  three 
principal  kinds  of  ship  timber,  viz.,  live- 
oak,  white  oak,  and  yellow  pine,  and 
will  be   of  incalculable   benefit   tc>   the 


*• 


MARINE    AND    NAVAL    ARCHITECTURE 


369 


naval  and  mechanical  interests  of  the 
United  States,  when  we  remember  that 
there  is  no  table  of  specific  gravity 
that  is  at  all  reliable  for  any  meridian 
of  North  America,  and  that  our 
mechanics  have  been  making  calcula- 
tions from  tables  of  specific  gravity 
found  in  European  works,  we  shall 
begin  to  approximate  a  conception  of 
its  value  ;  a  location  in  the  timbered 
districts  of  this  wooded  country  (for 
practical  purposes)  will  satisfy  the  most 
incredulous,  that  little  is  known  about 
the  productions  of  the  American  forest 
— a  location  of  two  years  for  this  pur- 
pose, satisfied  the  author  that  he  knew 
but  little  about  the  natural  science  of 
the  forest  timber  growth  of  the  United 
States.  We  are  doubly  gratified  to 
learn  that  this  important  and  responsi- 
ble trust  has  been  committed  to  Mr. 
James  Jarvis,  of  Virginia,  a  mechanic 
whose  unbending  energy  and  zeal  in 
the  discharge  of  duty,  fully  qualifies 
him  for  this  important  trust ;  and  hav- 
ing filled  the  office  of  Inspector  and 
Measurer  of  Timber  for  the  Govern- 
ment at  its  principal  depot  for  many 
years,  has  acquired  a  knowledge  of  its 


ments  for  the  first  year,  commencing 
on  the  15th  of  September,  1849,  and 
continuing  in  regular  order  up  to  the 
15th  of  August,  1850.  These  experi- 
ments will  perhaps  be  better  illustrated 
in  the  following  order: — On  the  15th 
of  September  he  received  in  12  feet 
lengths  the  butts  of  ten  trees  of  live- 
oak,  and  an  equal  number  of  white 
oak  and  yellow  pine.  Five  of  each 
kind  were  worked  square  at  the  place 
where  cut,  and  the  remaining  five  were 
brought  round  with  the  bark  on  ;  after 
their  arrival  they  were  subdivided  into 

3  feet  lengths.  The  squared  pieces  are 
from  12  to  15  inches  square  ;  the 
round  pieces  in  bark  from  12  to  15 
inches  in  diameter.  The  specific  gravi- 
ty of  each  piece  is  at  once  obtained, 
and  then  they  are  located  as  follows  : 

4  pieces  of  the  squared  live-oak  and  4 
pieces  of  the  round  live-oak  in  bark 
are  placed  in  tanks  under  cover,  where 
are  the  solutions  of  cor rosive  sublimate, 
copperas,  alum,  and  coal  tar.  The 
same  number  of  white  oak  and  yellow 
pine  pieces,  amounting  in  all  to  32 
pieces  of  each  species  of  ship  timber, 
one   half  of  which   are  square  pieces, 


defective   properties  to   an  extent   un-   the    other    half   round    and    in    bail;. 


surpassed  doubtless  by  any  man  in  this 
country.  Mr.  Jarvis  has  discretionary 
power  given  him  by  the  Department 
at  Washington  ;  he  has  kindly  furnish- 
ed us  with  the    result  of  his   experi- 


These  live-oak,  white  oak,  and  yellow 
pine  pieces  were  kept  in  the  tanks  sub- 
merged one  month,  at  the  expiration 
of  which  time  they  were  distributed  as 
follows  :    under    cover,    in     open    air, 


47 


370 


MARINE   AND    NAVAL    ARCHITECTURE. 


planted  as  posts,  and  laid  as  rail-road 
sills.  There  is  a  suitable  number  of 
the  pieces  which  have  not  been  pre- 
pared, also  under  cover,  in  open  air, 
planted  as  posts,  and  laid  as  rail-road 
sills  ;  a  proportion  of  the  pieces,  one 
square,  and  one  round,  are  water-sea- 
soned for  six  months  ;  after  being  re- 
moved from  the  water,  two  pieces  are 
made  of  one,  and  one  kept  under  cover, 
the  other  in  open  air.  The  pieces 
which  have  not  been  in  the  solutions, 
are  the  test  pieces  ;  amongst  these 
pieces  Mr.  Jarvis  has  fitted  some  to- 
gether, wood  and  wood,  except  having 
between  them  tarred  paper  coated  with 
charcoal  dust.  A  {ew  years  will  prove 
by  ocular  demonstration,  which  of  the 
solutions,  substances,  or  water,  will 
make  timber  most  durable.  The  pieces 
which  have  had  no  preparation  on 
them,  and  are  kept  under  cover,  are 
weighed  each  month,  to  observe  the 
amount  of  the  juices  or  moisture  lost 
by  evaporation  in  one  month  and  in 
one  year.  The  weighing  of  the  first 
piece  felled  in  September,  1849,  had 
been  weighed  twelve  times  in  August, 
1850  ;  therefore  it  will  take  until  Sep- 
tember, 1851,  before  the  timber  felled 
and  received  in  August,  1850,  can  be 
weighed  twelve  times.  The  object  in 
weighing  or  obtaining  the  specific 
gravity  each  month  in  the  year,  is,  that 
he  may  be  able  to  determine  the  best 


time  for  cutting  ship  timber,  or  whether 
it  is  of  any  material  consequence;  and 
by  testing  the  weight  of  the  same  kinds 
of  timber  in  connection  with  its  dura- 
bility,   and    thus    set    this    matter     at 
rest.      The  timber  used   for  these1   ex- 
periments is  thus  described: — The  live- 
oak   and   white    oak  are    of   excellent 
quality,  and  felled  purposely  for  those 
experiments,   with   a    few    exceptions. 
The  yellow  pine  is  not   as  good   as  is 
used  in  the  Navy  ;  its  speciric  gravity 
will  not  prove  the  fact.      The  very  best 
of  yellow   pine   is   not   of  the  greatest 
density.      Pitch-pine  is  not  as  good  for 
decks    or    deck   frames  as  other  fine- 
grained pine  from  the   south.     There 
is  a  species  of  yellow  pine  from  about 
Wilmington,    N.     C,    whose    speciric 
gravity  is  about  the  same  as  the  pine 
used  in   the  experiments,  and   corres- 
ponds (difference  of  time  when  cut  con- 
sidered) with   that   found  in  the  table 
of  specific  gravities  of  dry   timber — 
.610.      The  very  best  yellow  pine  tim- 
ber is  that  in  which  the  even  fineness 
of  the  grain  is  continued  to  the  centre 
or  pith    of  the  tree.     By   careful  ob- 
servation,  much    information   that    is 
valuable    may    be    obtained    from  the 
tables    of  specific    gravity.     Notwith- 
standing the  thickness  of  the  bark  on 
the  yellow  pine  and  its  lightness,  (the 
specific  gravity  differing  not  materially 
from   that   of  cork,)  we   find  that  the 


MARINE  AND  NAVAL  ARCHITECTURE. 


371 


pine  timber  in  bark  weighs  much  more    pine,  when  in  pieces  of  any  considera- 


than  the  square  timber;  this,  to  the 
casual  observer,  would  hardly  seem 
possible  ;  the  man  unacquainted  with 
the  nature  of  yellow  pine  sap-wood, 
would  be  likely  to  doubt  the  correct- 
ness of  the  table  ;  but  such  is  the  na- 
ture of  the  exterior  coating  immedi- 
ately  under  the  bark  of  yellow  pine, 
that  we  cannot  find  a  more  analogous 
substance  than  that  of  sponge  ;  its  re- 
tentive properties  are  very  similar,  and 
the  turpentine  with  which  this  sap- 
wood  is  saturated,  is  the  cause  of  its  in- 
creased specific  gravity  above  that  of 
the  squared  timber  when  covered  with 
bark.  The  thinner  the  sap-wood,  the 
less  the  specific  gravity.  There  is  an 
error  in  the  prevailing  opinions  in  re- 
lation to  the  durability  of  yellow  pine 
timber.  Our  Government  has  become 
a  heavy  stockholder  in  this  prevailing 
error,  by  acting  on  the  supposition 
that  yellow  pine  timber  required  a  great 
amount  of  seasoning.  The  conse- 
quence has  been,  that  large  timber 
houses  have  been  erected  and  filled  with 
yellow  pine  timber,  which  has  been 
kept  for  many  years,  and  when  in  a 
state  of  decay  has  been  used  both  for 
new  vessels  and  those  undergoing  re- 
pairs ;  this  is  a  great  mistake  ;  an  equal 
number  of  months  would  have  answer- 
ed a  better  purpose  than  as  many  years  ; 
as  it   regards  the  shrinkage  of  yellow 


ble  size,  it  shrinks  but  little  when  the 
vessel  is  in  active  service,  and  when 
used  as  deck  plank,  should  be  made 
narrow.  The  convictions  of  our  judg- 
ment lead  us  to  this  conclusion,  that 
yellow  pine  requires  no  seasoning  to 
make  it  durable  ;  the  ebb  and  flow  of 
turpentine  is  through  the  sap,  as  the 
specific  gravity  will  show ;  hence  we 
say,  that  the  capillary  tubes  of  the 
heart  wood  have  no  more  of  the  re- 
sinous property  (if  cut  at  a  proper  sea- 
son) than  is  required  for  strength,  and 
to  render  it  durable,  which,  we  think, 
Mr.  Jarvis's  experiments  will  fully 
prove.  The  continued  use  of  yellow 
pine  timber  in  the  private  ship-yards 
of  this  city,  have  already  proved  it  in- 
contestably;  we  could  name  ships,  built 
in  this  city  some  25  years  ago,  that  have 
their  first  yellow  pine  beams  in  their 
decks,  and  we  could  point  to  others 
that  have  exhibited  a  durability  in  their 
deck  frames  unknown  in  the  Navy  of 
the  United  States.  Proper  care  should 
be  taken  to  clear  the  timber  of  all  sap  ; 
and  as  it  regards  shrinkage  in  the 
naval  vessels,  if  the  same  measures 
were  adopted  as  in  the  private  yards 
of  making  strakes  of  plank  narrow,  we 
think  there  will  be  no  cause  of  com- 
plaint ;  the  strakes  of  deck  plank, 
clamps  and  bulwarks  of  Navy  vessels, 
are  too  icide.     There  is  another  error 


372 


MARINE    AND    NAVAL    ARCHITECTURE. 


in  that  of  preparing  yellow  pine  timber 
in  the  woods,  both  for  the  private  and 
for  naval  purposes,  it  being  absolutely 
necessary  that  the  sap  should  be  ex- 
cluded ;  the  timber  should  be  eight  in- 
stead of  four  squared,  thus  in  effect 
only  taking  off  the  sap,  (on  account  of 
the  very  best  of  the  timber  being  next 
to  the  sap ;)  this  would  enable  the 
builder  to  work  out  water-ways  and 
all  similar  pieces  without  cutting  in  as 
far  as  the  pith  on  the  exposed  side  of 
the  piece.  The  present  manner  of 
cutting  yellow  pine  timber  is  a  reckless 
waste  ;  the  very  best  parts  of  the  tree 
being  left  in  the  woods.  Inspectors 
measure  square  logs  clear  of  sap,  and 
the  consequence  is,  that  but  a  very 
small  three-cornered  strip  or  vein  of 
sap  is  left  on  the  corners  ;  whereas  if 
at  the  centre  of  the  length  of  the  log 
the  sap  were  removed,  and  the  log 
were  measured  as  in  other  girth  mea- 
surements, the  most  valuable  parts 
would  come  into  the  private  and  pub- 
lic yards ;  and  although  it  would  be 
somewhat  awkward  at  first  to  receive 
timber  in  this  manner,  being  accus- 
tomed to  the  square  log,  yet  the  price 
per  cubic  foot  would  actually  be  less, 
and  the  timber-getter  would  save  in 
labor  what  he  paid  in  extra  hauling 
and  freight,  and  not  only  so,  but  he 
would  get  paid  for  all  the  timber  he 
brought.       The     Government     would 


save  thousands  of  dollars,  besides 
having  better  pine  timber,  were  the 
Navy  department  to  have  yellow  pine 
forests  at  their  command  rather  than 
timber  sheds  stored  with  pine  timber, 
besides  retaining  the  life  of  the  timber 
by  not  having  the  turpentine  drawn 
from  the  tree  before  it  is  worked  into 
timber.  As  we  have  already  remarked, 
the  most  dense  timber  is  not  the  best, 
or  most  durable,  because  of  the  amount 
of  turpentine  it  contains  ;  it  is  often 
rendered  so  near  the  butt,  in  conse- 
quence of  the  tree  having  been  tapped 
while  standing,  in  order  to  draw  off  the 
turpentine.  We  would  prefer  the  quali- 
ty of  pine  we  have  alluded  to  in  its 
pristine  state  without  seasoning  for 
durability,  provided  it  were  properly 
ventilated  when  in  the  ship.  With  re- 
gard to  the  density  of  white  oak,  it 
may  with  strong  propriety  be  assumed 
that  the  quality  is  in  the  same  ratio  as 
the  density ;  but  we  shall  discover  that 
the  tables  of  specific  gravity  do  not 
furnish  an  index  for  determining  the 
best  quality,  inasmuch  as  they  show  the 
squared  white  oak  timber  cut  in  De- 
cember and  May,  to  be  the  heaviest 
when  cut,  while  at  the  same  time  that 
which  was  cut  in  January  and  July, 
was  of  the  best  or  better  quality.  In 
order  to  detect  this  supposed  discre- 
pancy, let  us  follow  the  subject  farther. 
The  timber  in  bark  will  show  that  our 


'+ 


MARINE    AND    NAVAL    ARCHITECTURE 


373 


first  conclusions  were  correct,  inas- 
much as  the  timber  cut  in  July  is  of 
the  greatest  density,  and  that  cut  in 
January  differs  but  a  trifle  from  that 
cut  in  December ;  hence  we  are  in 
evitably  brought  to  the  threshold  of 
this  conclusion,  that  no  table  of  specific 
gravities  for  white  oak  timber  is  relia- 
ble for  determining  the  quality,  unless 
its  weight  can  be  shown  in  the  bark. 
The  reason  of  this  discrepancy  between 
round  and  squared  timber  in  its  densi- 
ty, is  found  in  the  fact  that  the  texture 
of  the  grain  of  some  trees  is  better 
adapted  for  receiving  the  juices  than 
others  throughout  the  entire  transverse 
section,  while  others  receive  the  supply 
chiefly  through  the  sap.  This  latter 
kind  is  the  best  quality  ;  and,  as  a  con- 
sequence, is  likely  to  prove  the  most 
durable,  as  well  as  being  the  strongest. 
There  may,  however,  be  exceptions 
even  to  this,  as  a  general  rule.  With 
regard  to  the  specific  gravity  of  the 
live-oak,  as  shown  by  the  tables,  we 
clearly  discover  that  the  sap-wood  is 
lighter  than  the  heart,  inasmuch  as 
the  bark  being  thin,  could  scarcely  re- 
duce the  weight  as  much  as  shown  by 
the  tables.  The  tables  will  not  war- 
rant this  conclusion  of  white  oak,  inas- 
much as  we  find  that  which  was  cut 
in  March  was  heavier  in  bark  than 
when  squared.      But  although  the  sap 


of  live-oak  and  white  oak  is  less  dura- 
ble than  the  heart,  it  is  generally  re- 
ceived with  the  heart,  and  as  mer- 
chantable timber.  The  lasting  pro- 
perty of  live-oak  consists  chiefly  in 
its  being  entirely  void  of  that  acid  juice 
which  white  oak  contains;  but  this  is 
not  all,  the  whole  of  the  capillary 
tubes  seems  to  be  completely  coated 
and  filled  with  a  greasy  glutinous  sub- 
stance, that  is  not  found  in  the  sap, 
which  is  doubtless  the  reason  why  the 
sap  is  not  rendered  equally  durable ; 
this  substance  may  be  brought  out  for 
analyzation  by  steaming;  it  takes  steam 
nearly  or  quite  as  well  as  yellow  pine. 
The  monthly  tables  of  specific  gravity 
of  the  green  tree,  furnishing  as  they 
do  the  basis  of  (doubtless)  the  most  re- 
liable series  of  experiments  ever  un- 
dertaken in  this  or  any  other  country, 
will,  we  think,  be  examined  with  in- 
terest by  mechanics,  and  particularly 
those  whose  business  it  is  to  use  the 
three  kinds  of  timber  of  which  they 
take  cognizance.  In  addition  to  the 
monthly  tables,  Mr.  Jarvis  has  furnish- 
ed us  with  the  mean  specific  gravity, 
as  made  up  of  the  12  months,  and 
carried  the  whole  out  into  pounds  and 
ounces  avoirdupois.  We  then  have 
a  table  of  the  specific  gravity  of  dry  tim- 
ber, showing  when  and  where  cut. 


37  1 


THE    "GREEN    TREE." 


9pE(    ,,,,■    GRAVITY    OF    TIMBER     FRF.SII     FROM     THE     FOREST NONE    OF    WHICH     WAS    FELLED 

BEFORE    THE    SPECIFIC    GRAVITY     WAS    OBTAINED. 


MORE    THAN      TEN     DAYS 


LRE  live  oak. 

SQUARE    WHITE    OAK, 

SQUARE   YELLOW   PINE. 

.,   iN  i    1     c     l.i. KB. 

\  i  rv. 

MONTH    FELLED. 

SPECIFIC    GR  W1TV. 

IliS              <!/ 

1  037   =  04     i:; 
1  069  -  66    13 
l  058      66      2 
l  083  =  07     11 
1  068  :    66    12 
1.066  -  66    10 
1.044  =  05      4 
1.071       66    15 
1.102  =  68     1  1 
1.032  =  04      8 
U23  =  70      8 
1.082  =  07     10 

Mnvni    n  i 

r    I  on     on  1VITY. 

lbs.      oi. 

1.242   =  77     10 

1 .273  =  79      9 

1.274  =  79     10 
1.288  =  80      3 
1  283  =  80      3 
1.252  =  78      4 
1.261  =  78    13 
1.211    =  77     12 
1  258  =  78    10 
1.257  =  78      9 
1.239  =-  76    15 
1.246  =  77     18 

September  15th 

October  15th 

November  15th 

December  loth 

January  16th 

lbs.      oz. 

•  -  il     y 

October  I5th 

November  15th 

December  15th 

January  15th 

lary  15th 

October  15th.  .. 
November  15th . 
December  15th . 
January  15th . . . 
February  L5th.. 
March  15th 

,662  =  41       6 
.653       40    13 
639      39    15 

.025  =  39       1 
073  -  42       1 

.681  -  36      6 

April  I5tb 

Miv   15th 

May  15th 

\piil  15th 

,683  -  42    11 

May  l">th 

June  15th 

July  15th  

.688  -  36      7 

87      3 

Inlv  L5th 

July  15th 

.656  -  40    15 

i  12th 

Vui'tlst  15th 

.639  -  39    15 

ROUND   LIVE   OAK. 

ROUND   WHITE   OAK. 

ROUND   YELLOW   PINE. 

M  .\  I'll    r    i         D 

IP    CIPIC    i.li  WITV. 

MONTH    FELLED. 

SPEl  on     .,;:    \  ity . 

MONTH      l-'KI.!.      H 

ip   i    ,'..     r.u    v   rv. 

111*.       il/. 

1.114  =  71     10 
1 , 1 73  =  73      5 
1.182  =  73     14 

1.186  =  71      2 
1.194  =  74    10 
1   17:i  =  73       5 

1.187  71      5 
1.193  =  74      9 
1.182  =  73     14 
1.151  =  72       2 
1.148  =  71     12 
1,170  =  73       8 

lbs,      o/. 

,950      59      o 
997       62      5 
,996  =  02      4 
1.018  =  63    10 
1.015  =  63      7 
l.oi  l  =  63      6 
1  0711  =  0,7       7 
1.013  =  03       5 
1.021   =  68      13 

1.005  =  02    l:; 
1.089  =  68      1 

l  054  =  0,5    14 

lbs.      oz 

.828  =  51      12 

.70  1   ==  47     12 
.777  =  48       9 
705  —  47     13 

October  15th 

November  15th.  .  •  ■ 

October  15th.  .. 
November  15th. 
December  15th. 
January  15th.  . . 

October  15th 

November  loth 

Januat  v   I'.th 

January  15th 

February  loth 

^J 1  =  51       7 
789       49       5 

March   15th 

March  15th  • .".. 

782       48     14 

\|.|||     I'.lli 

May  15th  . .  .•.  .. 

June  15th 

July  15th. 

796  -  40    11 

May  L5th 

1  hi  ■  15th 

July  loth 

.7  11  =  46       8 
.7'.'2  =  49       8 
.751  =  46     15 
772  -  48       4 

June  15th 

July  15th 

August  12th 

August  15th 

August  15th 

MEAN   SPECIFIC  GRAVITY    FOR    ONE    YEAR. 

Square  pieces  of  Live  Oak (Fractions  off,) 1.259  =  78  pounds  11  ounces. 

Round           "               "         in  hark "              1.191  =  74  "  7 

Squa-:         "      White  Oak "             1.009  =  66  "  13  " 

Round          "              "         "            1.020  =  63  "  12  " 

Square         "      Yellow  Pine "            637  =  39  "  13  " 

Round          "               "          "            781=48  "  13  " 


DRY    TIMBER. 


KIND  OF  TIMBER. 

Kept  ilry  twenty  years,  anil 
where  felled. 

Kept  tlry  fourteen  years,  and 
where  felled. 

Kept  dry  two  years,  and 
where  felled. 

Kept  dry  until   supposed   dry 

enough  to  put  in  a  ship's 

deck. 

Specific  Gravity. 

lbs,  oz. 

1.065  =    66  12 

979  =61    3 

85 1  =  53    6 

.759  =  47    7 

.750  =  46  14 

733  =  45  13 

.680  =  42    8 

.603  =  37  11 

.571  =  35  11 

.530  =  33     8 

.530  =  33     8 

.418  =  20     2 

.418  =  26    2 

.610  =  38    2 

.518  =  32     0 

White  Oak 

(See  Note.) 

Ash 

Elm 

Comi i  Yellow  Pine.. . 

near  Wilmington,  N.  C* 

Baywood  Mahogany 



Note     This  is  a  part  of  the  keel  of  the  old  Macedonian,  taken  out  when  she  was  broken  up.     We  do  not  think  it  was  English  oak,  it 
being  very  i  o.M,       It  was  most  probably  cut  in  British  America.,  inasmuch  as  English  oak  is  of  as  much  density  as  ours. 


MARINE    AND    NAVAL    ARCHITECTURE. 


375 


We  have  shown   by  the  hydrostatic 
balance,    Fig-.    4,    in    chapter    I,    one 
method  by   which  the  specific  gravity 
of  any  body,  whether  a   floating  body 
or  one  more  dense,  may  be  determined. 
The    term    specific    denotes    that    its 
gravity  or  weight  is  determined  by  com- 
parison  with  water,  inasmuch  as  dis- 
tilled water  is  recognized  to  be  univer- 
sally the  same  when  pressed  under  the 
same  weight  of  air.      The  expositions 
given   on  page    28  of  the  manner   of 
using    the    hydrostatic    balance,     will 
doubtless    be   sufficient,  and  render  it 
unnecessary    to   extend    our    remarks 
upon  its  use  and  advantages.    Another 
remark  in    relation    to    the    durability 
of  timber,    (white   oak   in  particular,) 
when  in  a  green  state,  and  the  causes 
of  its  decay,  may  suffice.     It  is  doubt- 
less true  beyond  a  doubt,  that  in  many 
instances    more   than   one-half  of  the 
actual  gravity  of  timber  is  made  up  of 
the  juices  ;   hence  it  is  plain  that  the 
seasoning  process  is  but  a  removal  of 
this  moisture  by  evaporation  ;    the  in- 
quiry  then  follows,  which   is  the    best 
mode  of  evaporating  this  moisture,  by 
slow  or  sudden  means  ?    and  should  we 
be   deprived   of  the   use  of  the  timber 
while  this   operation  is  being  perform- 
ed ?     We  think  the  day  is  not  far  dis- 
tant, when  it  will  be  proved  by  ocular 
demonstration  that  timber  can  be  sea- 
soned in  the  vessel,    without    storage 


for  that  purpose,  by  a  proper  mode  of 
ventilation.      Experience    has    shown 
that  vessels  employed  in  hot  climates 
(unless  the  timber  be  well-seasoned)  rot 
in  a  very  short  time  ;   but  let  this  same 
vessel  be  employed  in  a  climate  colder 
than  that  in  which  she  was  built,  (or 
the  timber  was  cut,)  and  she  will  con- 
tinue   sound  for  years;   from   this   we 
may   learn,  that  vessels  built  of  green 
timber,    or     that     partially     seasoned, 
should   not  be  sent   on  stations  where 
the  order  of  seasoning  is  reversed,  and 
a  fermentation  of  the  acid  takes  place, 
which  will  rot  any  timber  vessel  within 
a  very  few  years.     Enough  might  be 
said  upon  this  subject  to  fill  a  volume, 
and   we  hope  that  the   untiring  zeal  of 
Mr.  Jarvis,  in  his  philosophical  investi- 
gations, will  elicit  such  information  as 
shall  fill  up  the  great   chasm  in   me- 
chanical   knowledge,  so   necessary    in 
the    construction    of  this    stupendous 
fabric,    and   upon    a  subject  of  which 
the  mechanical  world  is  avowedly  ig- 
norant, and  we  are  quite  well  assured 
in  our  own  minds  that  a  volume  upon 
this   subject   would   meet   with  public 
favor. 

But  to  return  to  the  subject  of  ven- 
tilation— we  say  that  there  is  abun- 
dant room  for  improvement  in  the 
Navy  of  the  United  States  in  this  par- 
ticular. In  the  Sloops  of  War,  as  in 
other  vessels  of  the  Navy,  an  air  strake 


376 


MARINE   AND    NAVAL    ARCHITECTURE. 


is  formed,  or  an  open  space  of  3  or  4 
inches  left  between  the  clamps  and 
sperketting  between  decks  ;  this  seems 
rather  as  a  conductor  of  foul,  than  of 
fresh  air  ;  we  should  rather  be  inclined 
to  the  belief,  that  were  those  openings 
closed,  and  the  ceiling  made  tight  by 
calking,  as  also  all  communication 
with  the  timbering  room  below  the 
upper  deck,  there  would  be  less  cause 
of  complaint.  The  only  communica- 
tion that  should  be  had  with  the  tim- 
bering room  should  be  above  deck, 
where  access  to  the  pure  open  air  can 
be  obtained.  This  mode  of  ventilation 
is  fully  accomplished  in  merchant 
ships,  and  at  the  same  time  water  or 
any  other  substance  than  air  is  not 
admitted  ;  it  is  true  that  between  the 
knees  and  the  deck  plank  the  air  may 
have  access,  but  the  channel  is  very 
small,  and  the  excess  of  draught  above 
would  neutralize  its  effect ;  a  vessel  is 
properly  ventilated  when  at  the  limber 
strake  an  apparatus  is  arranged  that 
shall  be  to  the  ship  what  the  fire-place 
is  to  the  house,  while  another  on  the 
plank-sheer,  port  sill,  or  rail,  shall  as- 
sist in  drawing  out  the  foul  air,  as  the 
smoke  is  drawn  upward,  the  timbering 
room  representing  the  chimney  ;  this 
may  be  placed  on  one  side  of  the  keel- 
son, while  on  the  opposite  side  of  the 
keelson  the  same  kind  of  instrument 
that    is  found  on  the   rail  of  the  first 


side,  and  the  fire-place  draught  on  the 
rail ;  this  reciprocal  change  alternately, 
it  will  be  perceived,  would  draw  out 
the  foul  air  on  one  side  and  supply  the 
fresh  air  from  the  opposite  side,  chang- 
ing alternately.  It  will  be  perceived, 
that  the  only  thing  required  to  accom- 
plish this  is  the  apparatus  for  the  gene- 
ration of  a  current  from  below,  and  the 
removal  of  obstructions  from  the  pas- 
sage above,  at  the  same  time  prevent- 
ing the  water  from  entering  through 
the  same  channel ;  this  has  recently 
been  partially  accomplished  in  some  of 
the  merchant  ships  of  this  city.  Free 
access  may  be  had  with  the  open  air 
through  an  orifice  in  the  plank-sheer, 
and  yet  the  water  cannot  enter,  inas- 
much as  the  orifice  is  closed  when  the 
bent  tube  is  submerged ;  this  is  done 
by  a  ball  simply  floating  into  the  orifice, 
which  effectually  closes  it  against 
water,  and  when  the  water  subsides, 
the  ball  drops  down,  when  air  is  admit- 
ted ;  this  contrivance,  though  simple 
and  useful,  and  doubtless  equal  if  not 
superior  to  any  other,  lacks  another  to 
be  placed  at  the  lowest  part  of  the 
timber  room  for  the  purpose,  as  we 
have  said,  of  generating  a  draught, 
which  will  effectually  draw  off  the  foul 
air,  which  causes  vessels  to  rot  so  much 
faster  in  the  naval  than  in  the  mer 
chant  service,  and  would  prove  much 
more  effectual  than  filling  the  timber- 


MARINE  AND  NAVAL  ARCHITECTURE, 


377 


• 


ing  room  with  salt,  which  has  prevailed    Corvette,)  stands  at   the  head   of  the 
to   a   very   considerable   extent.      The 
Sloops  of  War  of  the  Navy  should  have 
a  light  spar  deck,  and  there  are  several 
reasons  why  ;    first,  the   ship  would  af- 
ford greater    facilities  for  ventilation, 
and  if  advantage  were  taken  of  those 
facilities,  the  ship  would  be  more  dura- 
ble ;   another  reason   may  be  shown  in 
the  improved  health   of  the  crew.     It 
cannot    be   denied   that   pure   air,  or  a 
more  extensive  circulation  than  can  be 
obtained  below  the  gun-deck  of  a  Sloop 
of  War,  would  contribute  to  the  health 
and  comfort  of  the  crew.     On  the  coast 
of  Africa,  or  even  on  the   West  India 
station,  the  addition  would  be  of  incal- 
culable value,  inasmuch  as  a  free   cir- 
culation of  air  through  the  ports  might 
be    obtained,    and    benefit    the    entire 
crew,  who  could  suspend  their  ham- 
mocks to  the  spar  deck.      This  addi- 
tional deck  would  not  increase  the  bat- 
tery, nor  yet  the  number  of  men,  and 
surely  every  Sloop  of  War  should  have 
a  sufficiency  of  stability  to  carry  a  light 
spar  deck.      This  class  of  naval  vessels 
are  rendered  doubly  serviceable,  in  con- 
sequence   of  their  draught   of  water, 
which  is    sufficiently  light    to   enable 
them  to  have  ingress  and  egress  at  all 
the  ports  of  entry  of  any  considerable 
size;    and   next  to   the  War   Steamer, 
the  ship  commonly  called  the  Sloop  of 


list  for  usefulness.  In  this  age  of 
fire,  water,  and  vapor  power,  it  must 
be  admitted  that  the  War  Steamer  is 
most  reliable  as  an  engine  of  war  or 
a  messenger  of  peace.  It  must  not, 
however,  be  supposed  that  power  for 
weal  or  wo  in  a  War  Steamer  consists 
in  the  numbei  of  guns  mounted  in 
dread  array.  In  the  steamer,  as  in 
other  vessels  of  war,  a  small  number 
of  large  calibre  located  in  selected 
positions,  will  accomplish  wonders. 
But  the  main  object  in  their  construc- 
tion is  not  to  make  mere  floating  bat- 
teries ;  this  kind  of  vessel  belonged  to 
an  obsolete  age  ;  a  War  Steamer  is 
formidable  in  proportion  to  her  speed 
and  the  weight  of  her  shot ;  a  single 
swivel  gun,  carrying-  a  10  or  12  inch 
shot,  is  more  formidable  than  a  broad- 
side of  42  pounders  ;  and  a  War 
Steamer,  carrying  12  eight  or  nine 
inch  guns,  and  2  twelve  inch  pivot 
guns,  would  be  of  much  greater  ser- 
vice than  the  Pennsylvania  with  her 
three  gun-decks  and  spar  deck,  pro- 
vided she  could  use  them  all. 

With  regard  to  the  relative  excel- 
lence  of  the  models  of  naval  and  com- 
mercial steamers,  the  latter  very  far 
surpasses  the  former  in  the  United 
States.  As  we  had  occasion  to  re- 
mark in  relation  to  commercial  steam- 
War,  (more  properly  denominated  the  I  ers,  that  to  be  profitable,  they  must  be 

48 


378 


MARINE    AND    NAVAL    ARCHITECTURE 


/;ist  ;  so  we  say  of  War  Steamers,  to 
be  serviceable,  they  should  be  fast. 
He  who  is  behind  in  this  age  of  the 
world,  is  ever  chasing  lost  time,  a 
part  which  the  American  character 
repudiates.  We  would  not  be  misun- 
derstood in  this  matter  ;  we  do  not  say 
that  commercial  steamers  are  better 
vessels,  but  that  they  are  better  models 
for  this  great  desideratum,  viz.,  speed, 
and.  consequently,  are  preferable  for 
War  Steamers.  Instead  of  being  be- 
hind, they  should  be  even  faster  than 
those  of  the  merchant  service.  It  is 
evident  that  the  two  kinds  of  vessels 
require  the  same  models,  inasmuch  as 
they  both  aim  at  the  same  important 
points,  viz.,  stability,  speed,  and  easy 
draught  of  water.  A  steamer  for  com- 
mercial purposes  must  be  able  to  go  in 
and  out  at  the  ports  for  which  she  is 
destined  ;  and  a  War  Steamer  should 
be  able  to  enter  almost  any  port  where 
fuel  may  be  obtained.  All  commercial 
steamers  of  any  considerable  size  should 
be  so  constructed  that  they  may  at  any 
time  be  converted  into  War  Steamers; 
this  could  be  accomplished,  and  the 
Government  at  all  times  would  have  a 
respectable  force  in  steamers,  that 
would  be  in  advance  of  other  nations; 
this  could  be  accomplished  without 
material  additional  cost  of  construc- 
tion ;  it  would  only  be  necessary  for 
the  Government  to   know  the  quality 


of  the  vessels  built,  in  the  same  man- 
ner that  the  underwriters  do,  and  this 
to  the  Government  would  be  but  fur- 
nishing employment  for  those  already 
under  pay,  thus  (we  have  assumed  that 
naval  officers  would  be  selected  for 
this  mechanical  operation,  as  has  al- 
ways been  the  case)  not  only  millions 
of  dollars  might  be  saved  to  the  Gov- 
ernment, but  the  mortifying  reflection 
that  her  steamers  were  behind  the  age, 
notwithstanding  they  had  cost  more 
than  enough  to  place  them  in  advance 
— they  were  comparatively  slow,  though 
they  had  cost  enough  to  render  them 
efficient.  The  continuation  of  the 
former  practice  of  modelling  vessels  of 
war,  as  well  as  other  vessels,  for  gene- 
rations yet  unborn  to  build,  is  entirely 
wrong,  as  whole  frames  of  steamers 
and  other  vessels  bear  witness ;  these 
frames  were  cut  to  the  moulds,  and 
bevels  made  by  models  the  Govern- 
ment have  repudiated,  and  the  timber 
is  condemned  because  of  its  having 
been  shaped  out  by  an  inferior  model ; 
we  say  the  promiscuous  timber  used 
in  the  private  yard  is  far  better  adapt- 
ed to  working  the  ship's  frame,  than 
that  which  is  worked  out ;  any  me- 
chanic can  mould  out  a  better  frame 
where  he  has  the  variety  of  crooks 
before  him  on  the  ground,  than  when 
selecting  the  shape  from  the  tree  while 
standing.       The    strength    of    Ocean 


MARINE    AND    NAVAL    ARCHITECTURE. 


379 


Steamers,  whether  for  commercial  or 
war  purposes,  should  be  unquestiona- 
ble ;  and  the  one  requires  quite  as 
much  as  the  other  ;  and  all  the  means 
we  have  named  for  adding  strength  to 
the  commercial  is  equally  applicable  to 
the  War  Steamer.  Few  steamers  that 
are  very  fast  carry  much  freight,  but 
doubtless  quite  enough  to  be  equal  to  an 
amount  of  armament  sufficient  both  in 
calibre  and  extent  for  a  War  Steame 


1  * 


in 


addition  to  her  provision  and  fuel.  The 
weight  of  War  Steamers  differs  but  lit- 
tie,  from  i  to  TV  of  their  load-line  dis- 
placement ;  much  of  this,  however, 
depends  upon  their  principal  dimen- 
sions, as  well  as  their  shape ;  no  pro- 
portion of  the  registered  tonnage  can 
by  any  possibility  apply  to  the  weight 
that  may  be  considered  a  reliable  rule, 
inasmuch  as  any  alteration  in  the  di- 
mensions would  increase  or  diminish 
the  weight ;  for  example,  we  may  add 
to  the  depth  5  feet,  and  take  off  the 
breadth  but  one  inch,  and  the  tonnage 
is  less,  although  the  ship  would  weigh 
perhaps  10  per  cent.  more.  The  car- 
penter's measurement,  or  any  other 
than  that  of  the  displacement,  is  not  a 
reliable  standard.  The  remarks  found 
on  page  345  in  relation  to  the  shape 
of  the  bow  of  an  ocean  steam-ship  will 
be  found  equally  applicable  to  those 
intended  for  war  purposes.  It  requires 
but   a  mechanical  glance   to   discover 


that  the  line  of  flotation  of  every 
steamer  in  the  Navies  of  the  Old  or 
New  World  are  fullest  at  the  stem, 
and,  as  a  consequence,  the  bulk  of  the 
wave  generated  by  the  bow  is  found  at 
the  wood  ends,  or  along  the  bow  close 
by  the  stem  ;  this  must  of  necessity  be 
the  case  on  every  bow  that  has  a  lon- 
gitudinally round  line  of  flotation,  and 
in  Chapter  10  we  contrasted  the  mo- 
tions of  the  narrow,  straight-sided  and 
round  bow  of  the  steamer  at  sea,  to  her 
suspension  in  the  turning  lathe ;  so 
with  regard  to  the  longitudinal  motion 
on  the  bow  that  has  this  fullness  at  the 
extremity.  The  man  who  doubts  the 
tangibility  of  the  demonstration  we 
have  given,  needs  but  to  apply  the  pro- 
tractor to  the  bow  of  any  vessel  having 
a  line  of  flotation  continued  round  to 
its  extremity,  and  he  will  at  once  dis- 
cover that,  as  we  have  said,  the  fullest 
part  of  the  bow  is  at  its  extremity  ; 
and  if  fullness  and  resistance  mean  any 
thing,  he  must  admit,  (however  unwill- 
ing,) that  the  greatest  part  of  the  re- 
sistance on  the  bow  is  at  the  wood 
ends  ;  that  is  to  say,  the  same  area  at 
that  part  has  more  resistance  than  an 
equal  amount  of  surface  any  where 
else,  or  at  any  other  part  ;  we  have 
been  thus  particular  in  defining  our 
position,  inasmuch  as  we  are  but  too 
well  convinced  that  it  conflicts  with 
the  hereditary  notions  of  the  age,  and 


Ci 


380 


MARINE    AND    NAVAL    ARCHITECTURE. 


that  it  will  meet  with  more  opposition 
on  both  shores  of  the  Atlantic  Oceau 
than  almost  any  other  that  might  be 
demonstrated  with  an  equal  amount 
of  tangibility  ;  but  the  candid  man  will 
look  at  the  position  taken  in  all  its 
bearings,  and  if  his  perceptive  powers 
are  not  remarkably  obtuse,  we  have  no 
fears  of  the  result. 

In  defining  the  proper  shape  for 
war  vessels,  we  are  well  aware  that 
we  are  navigating  a  dangerous  coast ; 
the  dogmatical  supremacy  assumed  by 
this  branch  of  the  Government,  would 
lead  the  casual  observer  to  believe  that 
here  was  the  consummation  of  the  per- 
fective qualities  to  be  found,  and  no 
where  else :  but  a  careful  and  close 
observation  has  taught  commercial 
men  that  this  (once  the  right)  arm  of 
national  power  is  diseased,  and  that 
unless  a  cure  is  speedily  effected,  am- 
putation must  inevitably  be  rendered 
necessarv.  England  has  learned  this 
truth,  that  her  Navy  (itself  considered) 
could  not  keep  pace  with  her  mari- 
time interests ;  hence  she  found  it  ne- 
cessary to  foster  such  a  direction  of  in- 
dividual enterprise  as  could  be  made 
available  for  national  purposes  ;  how 
far  a  similar  course  may  be  made 
available  for  the  better  security  of  na- 
tional honor  on  the  part  of  the  United 
Slates,  it  is  not  our  purpose  to  ex- 
amine,   or    our    province    to    discuss. 


We  say  this,  that  a  few  War  Steam- 
ers, capable  of  carrying  a  battery  as 
has  been  designated  in  this  Chapter, 
and  provision  and  water  for  one  month, 
and  capable  of  being  driven  15  miles 
per  hour,  (which  should  be  considered 
a  moderate  speed  for  a  War  Steamer,) 
would  be  more  formidable  and  efficient 
than  all  the  registered  Navy  of  the 
United  States.  This  desirable  quality 
can  only  be  accomplished  by  large 
vessels — a  steam-ship  even  of  2000 
tons  is  a  small  affair  for  naval  purposes; 
if  she  has  any  considerable  amount  of 
power,  she  is  entirely  full  with  nothing 
but  her  engines  and  coal,  and  even  for 
a  light  draught  of  water,  (not  exceed- 
ing ten  feet,)  a  steamer  cannot  be  built 
(that  shall  be  adapted  to  all  the  pur- 
poses of  war)  of  a  smaller  tonnage  than 
2500.  War  steamers  need  not  draw 
a  heavy  draught  because  they  are 
large — 16  feet  is  a  sufficient  draught 
for  a  steamer  of  3000  tons.  A  vessel 
as  already  described,  drawing  but  10 
feet  water,  would  require  a  great 
breadth,  with  reduced  depth,  and  an 
easy  bilge,  to  prevent  her  rolling  ;  her 
depth  should  be  even  less  than  half  of 
the  breadth,  and  she  would  require 
additional  strength  on  the  sides,  and  at 
every  available  part  ;  for  example,  the 
coal  bunkers,  that  have  been  merely 
regarded  as  bulk-heads  to  confine  the 
04ml  within  certain  limits,  may  be  made 


MARINE    AND    NAVAL    ARCHITECTURE. 


381 


to  add  very  materially  to  the  strength 
of  the  ship,  extending  through  each 
transverse  bulk-head. 

We  have  shown  at  different  parts  of 
the  work  the  proper  measures  for  in- 
creasing the  strength  of  vessels  ;  and 
Ocean  Steam-ships,  whether  for  com- 
mercial or  for  war  purposes,  require 
all  the  strength  that  can  be  made 
available  with  the  ordinary  means. 

Our  Government  determined  to  build 
a  War  Steamer  some  years  since  for 
harbor  defence,  and  after  having  pur- 
chased iron  for  the  purpose,  the  pro- 
ject was  abandoned,  at  least  for  the 
present. 

Experiments  in  England  have  proved 
the  futility  of  attempting  to  render  the 
sides  of  iron  vessels  impenetrable  by 
shot.  We  are  persuaded,  however, 
that  the  most  formidable  description 
of  vessel  for  harbor  defence  would  be 
such  as  carried  no  guns,  presenting  an 
angle  that  would  be  impenetrable  by 
shot ;  such  vessel,  built  of  iron,  and 
driven  at  a  speed  of  25  miles  per  hour, 
would  go  into  the  broad-side  of  any 
vessel  quite  as  far  as  would  be  neces- 
sary to  sink  her  in  a  few  minutes,  with- 
out the  firing  of  a  single  gun  ;  this  ves- 
sel might  be  so  completely  housed  and 
made  shot-proof  that  its  crew  would  be 
securely  protected,  being  so  sharp  that 
neither  the  hull  nor  its  cover  could  be 
affected  by  shot.      The  power  of  sttoh 


a  vessel  to  strike  a  blow,  the  effects 
of  which  we  have  described,  may  be 
judged  from  the  effects  of  a  collision 
of  one  of  the  comparatively  frail  steam- 
boats on  the  Hudson  river:  an  ordi- 
narily sharp  boat  will  cut  a  sound 
sailing  vessel  in  two,  and  at  the  same 
time  the  shock  will  scarcely  be  felt  in 
the  ladies'  saloon,  or  at  the  captain's 
office,  while  the  boat  herself  is  not 
materially  injured.  Collisions  of  this 
kind  have  fully  proved  that  the  sharper 
the  vessel,  the  more  of  longitudinal 
strength  she  possesses  ;  and  if  we  but 
contemplate  a  vessel  built  for  strength 
and  speed,  we  may  readily  conceive  of 
its  power  to  strike  a  blow  that  no  ves- 
sel could  resist — it  would  be  equal  to 
that  of  a  train  of  rail-road  cars  of  equal 
weig'ht  running  into  an  embankment 
at  the  speed  already  named.  Guns 
for  harbor  defence  should  be  on  terra 
firma  ;  they  are  little  better  than  a 
useless  appendage,  for  the  protection 
of  the  harbors  or  bays  of  our  exten- 
sive coast. 

With  regard  to  the  application  of 
power  for  propelling  War  Steamers, 
the  side  paddle  wheel  is  objectionable, 
on  account  of  its  exposure  to  shot, 
and  the  inequality  of  the  dip  on  the 
two  sides ;  the  smallest  roll  effects  a 
material  change  in  the  dip  of  the 
bucket,  even  if  the  vessel  should  not 
roll,   but    remain   perfectly   stable,  this 


382 


MARINE    AND    NAVAL    ARCHITECTURE 


chancre  would  take  place,  and  cause  a    the  features  of  which  appear  to  be  like 


loss  of  power ;   with  the  side  wheel  a 
larger  amount  of  dip  is   necessary,  in 
order  to  seen  re  a  continued  unvarying 
resistance  from  the  wheel.      The  pro- 
peller in  some  respects  might  be  con- 
sidered preferable  for  War   Steamers, 
but    the     seeming    advantage    arising 
from  its  security  against   shot    by  its 
peculiar    location,  is  counteracted  by 
the   difficulty  in   making   repairs;  the 
vessel  must  be  docked  when  the  small- 
est   amount    of  repairs  are   required. 
As  it  regards  the   effective  qualities  of 
those  two  modes  of  applying  the  power 
for  propelling  steam-ships,  we  are  per- 
suaded the  side  wheel  is  preferable,  in- 
asmuch   as    the   geering    necessary    to 
obtain  the  required  speed  of  the  pro- 
peller, adds  to  the    risk,  and    renders 
this  mode  of  application  more  liable  to 
derangement  than  a  more  direct  ap- 
plication,  which  the  side  paddle  wheel 
is  recognized  to  be  ;  this,  in  connection 
with  the  ready  manner  in  which  the 
side  wheel  can  be  repaired,  renders  it 
preferable.     We  are  persuaded,  how- 
ever, that  there  is  a  wide  field  for  im- 
provement in  the  propulsion  of  steam- 
ships.     In  relation  to   the   security  of 
the   machinery  against   shot,  the   coal 
bunker  when  full  would  furnish  some 
protection. 

The  question  has  been,  and  is   now 


the  following  :  provided  the  propeller 
can  be  unshipped,  or  by  a  coupling 
joint  be  lifted  out  of  water,  to  enable 
the  sails  to  be  used  to  advantage,  would 
it  not  be  preferable  to  the  side  wheel? 
The  same  may  be  said  of  the  side 
wheel:  the  buckets  or  paddles  may  be 
taken  off;  not,  however,  without  diffi- 
culty when  at  sea. 

With  regard  to  the  propriety  of 
sparring  War  Steamers  with  the  same 
weight  of  spars  that  a  sailing  ship  of  the 
same  size  would  carry,  we  say  the  prac- 
tice is  manifestly  wrong.  They  are  only 
required  as  jurymasts,  to  be  used  when 
any  derangement  of  the  machinery 
takes  place.  Steam  and  sail  work  very 
well  together  when  the  wind  is  fair, 
but  the  steam-ship  that  cannot  be 
worked  in  an  open  sea  without  sail,  m 
a  poor  affair,  either  in  model  or  power  : 
a  vessel  whose  principal  advantage 
consists  in  being  able  to  help  sailing 
vessels  when  unable  to  help  them 
selves,  herself  depending  upon  sail  foi 
the  faithful  performance  of  her  duty, 
renders  her  at  once  unworthy  of  the 
name  she  bears ;  apart  from  another 
consideration,  that  they  have  enough 
to  carry  without  this  unnecessary  ap- 
pendage, an  equal  weight  in  coal  would 
be  of  much  more  service.  War  Steam- 
ers furnish  abundant  room  for  improve- 


agitated,  resolving  itself  into  a  problem,    ment  in  almost  every  part. 


*s 


MARINE  AND  NAVAL  ARCHITECTURE. 


3S3 


Having  shown  in  our  remarks  on 
river  steamboats  the  manner  of  com- 
puting horse  power,  and  what  are  the 
disadvantages  of  the  ordinary  side  pad- 
dle-wheel for  Ocean  Steam-ships,  we 
should  prove  recreant  to  our  purpose 
did  we  not  show  what  has  been  done 
by  way  of  improvement  in  the  applica- 
tion of  power  on  War  Steamers  as  well 
as  Coasting  Steamers  in  Europe,  and 
contrast  those  improvements  with  what 
has  been  done,  and  is  now  doing,  in  the 
United  States.  In  England  an  im- 
provement has  been  introduced — the 
wheel  of  Win.  Morgan  has  been  suc- 
cessfully applied,  not  only  to  steamers 
running  coast-wise,  but  the  War 
Steamer  Medea,  of  about  S00  tons,  and 
220  horse  power,  has  been  made  the 
subject  of  this  experimental  wheel,  and 
has  shown  its  superiority  over  the  or- 
dinary wheel.  The  Morgan  wheel  has 
the  advantages  of  entering  and  leaving 
the  water  vertically — a  quality  not  pos- 
sessed by  the  side  paddle  wheel.  Its 
reputation  in  England  has  been,  and 
is  still,  such  as  to  render  it  worthy  of  a 
more  extended  notice  than  our  pages 
will  justify — its  description  may  be  seen 
in  the  works  of  Tredgold. 

While  England  has  been  improving, 
Americans  have  not  been  idle.  The 
wheel  of  Mr.  Abner  Chapman,  of  this 
city,  is  worthy  of  notice.  This  wheel, 
after    having    had    several    successful 


trials,  has  been  placed  on  the  steam- 
boat Santa  Claus. — Length  208  feet  ; 
breadth  25  feet  ;  draft  of  water  5  feet ; 
cylinder  48  in  diameter ;  10  feet 
stroke  ;  diameter  of  wheel  25  feet  ;  7 
feet  face  ;  24  revolutions  per  minute. 
The  velocity  of  this  boat  was  ^91  per 
minute,  or  0485  per  second ;  relative 
velocity  at  periphery  of  wheel  £%  per 
second,  or  £%$  per  hour  ;  relative  velo- 
city at  centre  of  pressure  4^0  per  second, 
or  3.17  per  hour.  The  gain  on  Chap- 
man's patent  wheel  equals  15  per  cent, 
of  former  speed  of  boat ;  calling  the  slip 
of  the  flat  bucket  unit  or  1,  the  slip  of 
Chapman's  bucket  equals  .57  at  the 
centre  of  pressure  of  the  wheel.  The 
buckets  of  this  wheel  are  made  of  plate 
iron  in  two  parts,  and  of  a  curved 
form,  running  from  the  side  arms  to 
the  next  centre  arm  back,  with  an 
opening  between  them  at  the  centre 
arm  of  half  an  inch  to  each  foot  of  di- 
ameter of  wheel ;  the  ratio  of  gain  of 
this  wheel  is  about  equal  at  all  immer- 
sions, which  is  not  the  case  with  the 
Morgan  wheel. 

On  Chapman's  wheel  all  parts  are 
fixed  permanently,  while  on  the  Mor- 
gan wheel  the  buckets  are  worked  by 
an  eccentric  arm;  and  by  the  number 
of  moveable  parts,  it  must  of  necessity 
be  both  expensive  in  its  construction 
and  repairs. 


384 


MARINE    AND    NAVAL    ARCHITECTURE. 


CHAPTER   XII. 

Laws  of  Beauty  and  Taste — Heads  and  Sterns — Compend  of  all  the  Rules  for  Masting  and  Sparring  Ves- 
sels of  all  description — the  Author's  Improvements. 


The  French  rhetoricians  have  a 
maxim  that  there  is  nothing  beautiful 
that  is  not  true — an  axiom  that  ap- 
plies to  ships  as  well  as  other  things. 
From  time  immemorial  first  impres- 
sions have  been  well  nigh  omnipotent, 
and  men  have  in  all  ages  set  a  value 
upon  those  impressions  above  all  price, 
and  in  by  far  the  greatest  number  of 
instances,  the  impressions  made  at  first 
sight  have  followed  their  possessor  to 
the  threshold  of  the  grave.  The  Chi- 
naman is  doubtless  quite  as  tenacious 
about'  the  size  of  the  eye  he  paints  on 
the  bow  of  his  Junk  as  the  ship-builder 
of  modern  times  would  be  about  the 
size  of  the  hawse-hole,  and  in  both 
cases  the  constructor  would  be  gov- 
erned as  he  supposed  by  the  principle 
of  utility.  How  important  then  that 
the  principles  of  utility  should  form  the 
mechanical  alphabet  for  the  inexpe- 
rienced, and  not  the  opinions  of  others! 
There  is  a  certain  fitness  that  is  char- 
acteristic of  every  art,  and  although 
there  are  few  indeed  who  can  follow 


in  their  mind's  eye  all  the  various  parts 
of  this  stupendous  fabric  in  detail,  yet 
to  us  the  reason  appears  obvious  :  they 
have  never  allowed  themselves  to  think 
independently  of  the  opinions  of  others; 
this  practice  has  been  continued  until 
they  cannot  think  for  themselves,  and, 
as  a  consequence,  they  are  fettered  by 
the  opinions  of  others.  We  hold  that 
no  man  can  improve  to  any  considera- 
ble extent  either  in  ship-building  or  any 
other  branch  of  mechanism,  whose 
volitions  are  not  the  result  of  his  own 
conceptions. 

With  regard  to  beauty  in  ships,  we 
have  said  that  it  consisted  in  fitness 
for  the  purpose  and  proportion  to  effect 
the  object  designed.  The  eye  of  many 
men  remain  uncultivated  for  a  whole 
life-time,  in  consequence  of  their  not 
having  studied  the  analogy  of  propor- 
tions, found  only  in  nature  ;  the  con- 
sequences have  proved  fatal  to  the  phi- 
losophy of  mechanism  ;  let  the  branch 
be  what  it  may,  proportion  is  the  uni- 
versal   alcahvst,  and   dissolves    before 


MARINE    AND    NAVAL    ARCHITECTURE, 


385 


the  cultivated  eye  the  mightiest  fabric 
into  one  of  smaller  magnitude — this  is 
as  equally  true  of  the  pyramid  as  of 
the  ship  ;  it  is  seen  in  nature  from 
the  mighty  oak,  (the  monarch  of  the 
wood,)  whose  giant  arms  have  dared 
the  blasts  of  an  hundred  winters,  down 
to  the  smallest  shrub  ;  all  Nature 
teaches  us  that  her  works  appear  to 
the  eye  smaller  than  they  really  are. 

We  were  led  to  these  reflections 
from  a  knowledge  of  this  fact,  viz.,  that 
a  great  many  ships  are  built  whose  ap- 
pearance is  really  disagreeable  to  men 
of  taste  on  account  of  the  clumsy  ap- 
pearance they  present,  consequent 
upon  the  heavy  appearance  of  the 
head  or  stern,  or  some  other  part  that 
may  be  disproportioned.  It  is  not  the 
many  mouldings  on  a  ship,  or  the 
amount  of  carved  work  on  the  head 
and  stern,  that  makes  her  appear  to 
have  life  ;  so  far  from  adding  to  the 
appearance  of  a  handsome  ship,  they 
detract  from  it,  and  it  is  only  the  dis- 
proportioned ship  that  requires  those 
external  superfluities  to  make  her 
passable  ;  indeed,  we  have  often  seen  a 
ship  that  exhibited  a  much  handsomer 
stern  with  nothing  on  it,  than  another 
with  a  fall  tafterel.  These  remarks 
apply  with  equal  propriety  to  the 
head ;    the   setting    of  a   head   on   the 


construction,  inasmuch  as  the  eye  must 
determine  its  every  part,  and  we  some- 
times see  ships  that  fully  exemplify 
this.  There  is  a  certain  effect  conse- 
quent principally,  but  not  entirely,  upon 
the  sheer  and  the  rake  of  the  stem  : 
those  lines,  if  proper  attention  is  paid 
to  their  direction,  will  furnish  a  point 
to  which  every  part  should  tend.  If 
the  bow  be  longitudinally  sharp,  or 
have  a  very  considerable  rake,  the  cut- 
water should  extend  farther  out  than 
though  it  were  less  sharp,  or  had  less 
rake.  This  leads  us  to  another  con- 
clusion, viz.,  that  the  chances  for  se- 
curing a  long  head  are  less  on  the 
sharp  than  on  the  full  vessel  ;  hence  it 
will  appear  quite  manifest  that  a  just 
medium  should  be  observed,  and  if  the 
ship  should  appear  to  require  a  long 
head,  it  should  be  reduced  vertically. 

We  completed  our  expositions  on 
the  general  outline  of  the  construction 
of  a  ship  (with  the  exception  of  the 
head  and  stern)  on  page  315  ;  we  shall 
now  follow  up  the  connection,  and 
finish  the  ship. 

On  Plate  4  we  have  illustrated  the 
manner  of  laying  down  the  stern  on 
the  floor ;  the  detailed  description  of 
the  manner  in  which  this  part  of  the 
operation  is  performed  may  be  found 
on  page  13S.     When  the  stern  is  thus 


bow  of  a  ship  has  been  considered   to"  laid  down  on  the  floor,  the  side   coun- 
be  one   of  the  most  difficult  parts  of  ter  timbers  are  worked  out  in  the  same 


49 


3SG 


M  A  K  I  N  E   A  N  D    NAVAL    ARCHITECTURE, 


manner  as  any  other  timber  of  the 
frame  ;  they  are  also  raised  and  se- 
cured to  the  ribband  at  the  rail  height ; 
there  should  be  a  harpen  made  at  the 
height  of  the  rail,  the  top  of  which 
should  range  with  the  sheer;  this 
would  be  all  the  ribband  that  would  be 
required;  the  timbers  being  worked 
out  by  the  counter  timber  moulds, 
would  find  their  proper  location  on  the 
transom  ;  it  being  assumed  that  the 
distribution  of  the  counter  timbers  has 
been  so  arranged  that  the  cabin  win- 
dows will  come  between  the  timbers, 
and  taper  as  we  advance  toward  the 
outside  from  the  centre,  as  in  Fig.  1  of 
Plate  26. 

The  practice  which  now  prevails  al- 
most universally  of  building  sterns,  is 
as  follows :  the  side  counter  timber  is 
made  to  conform  in  its  rake  with  a 
mould  that  is  temporarily  nailed  to  the 
side  of  the  stern  post ;  two  half  tim- 
bers are  also  worked  out,  extending 
no  higher  than  the  arch-board  is  de- 
signed to  go  ;  along  side  of  these  half 
timbers  on  each  side  of  the  post,  a  coun- 
ter timber  extends  to  the  rail,  and  is  fast- 
ened to  the  post ;  the  reason  for  keep- 
ing the  counter  timbers  off  from  the  post 
by  half  timbers  is,  that  the  rudder-stock, 
which  is  larger  than  the  post,  may  not 
cut  the  whole  timbers  ;  a  second  rea- 
son is,  that  the  windows  could  not  be 
properly  divided  with  the   centre  tim 


bers  so  close  together.  When  the 
centre  and  the  corner  timbers  are  in 
their  place,  a  ribband  is  extended 
across  the  stern  at  the  heads,  or  a  short 
distance  below,  and  the  arch-board  is 
then  extended  across  the  stern  ;  it  will 
be  discovered  that,  as  we  have  shown 
in  Plate  4,  the  arch-board  rakes  at  a 
different  angle  from  that  of  either  the 
stern  or  the  counter;  that  it  is  ad- 
justed between  the  two  angles ;  the 
stern  timbers  above  the  arch-board 
bein^  straight,  no  other  ribband  is  ren- 
tiered  necessary.  It  is  customary  to 
give  the  arch-board  about  the  same 
vertical  round  as  the  beam  mould  ;  this 
would  require  much  more  on  the  board 
itself,  inasmuch  as  its  rake  and  round 
combined,  demands  much  more  sni  or 
crook  edgewise,  in  order  to  obtain  the 
round  of  the  beam  mould  above  a  hori- 
zontally straight  line.  We  have  shown 
in  Fig.  1,  Plate  8,  the  manner  of  ob- 
taining a  true  sweep  for  the  arch-board, 
after  we  have  determined  how  much 
sweep  we  require  ;  the  board  is  usually 
of  oak,  and  the  same  in  thickness  as 
the  plank  on  the  counter  and  stern  ; 
its  width  for  the  smallest  ship,  as  we 
have  said,  is  seldom  less  than  12  inches 
at  the  centre,  and  somewhat  less  at  the 
side  of  the  stern  ;  the  ends  are  usually 
extended  quite  across  the  wale,  and 
are  shown  on  the  outside,  until  covered 
with    the    quarter    piece;    below    the 


* 


*>*-- 


I 


V      .. 


MARINE    AND    NAVAL    ARCHITECTURE. 


3S7 


arch-board  the  ends  of  the  wales  are 
partially  cut  with  a  mil  re  for  several 
st rakes  down,  when  the  mitre  be- 
comes more  complete,  and  extends 
quite  across  the  transom  to  the  post; 
thus  it  will  be  perceived  that  some  of 
the  ends  of  the  wales  are  seen  below 
the  arch-board,  as  we  have  said,  for 
several  strakes.  We  do  not  think  this 
mode  a  good  one,  for  the  following  rea- 
sons: in  calking  the  cross  seam  in  its 
continuation  from  the  post  to  the  arch- 
board,  that  part  where  the  mitre  is  in- 
complete has  a  tendency  to  start  the 
wales  off",  inasmuch  as  the  seam  makes 
the  ends  of  the  counter  plank  much 
nearer  square  than  those  of  the  wales. 
We  have  mitred  the  entire  seam  below 
the  arch-board,  and  deem  it  preferable 
to  the  present  mode  ;  above  the  arch- 
board  all  the  plank  extend  quite  across 
the  stern  ;  it  has  been  the  custom  to 
plank  the  stern  above  the  upper  arch 
(which  forms  the  vertical  size  of  the 
cabin  windows)  promiscuously,  or  with- 
out reference  to  the  direction  of  the 
seams,  and  then  lining  the  stern  above 
and  below  the  tafferel  ;  but  this  prac- 
tice is  objectionable,  inasmuch  as  it 
causes  the  stern  to  rot  sooner  than 
other  parts,  besides  it  does  not  look  so 
well ;  the  stern  should  be  planked  with 
narrow  strakes,  not  certainly  wider 
than  the  deck  plank,  and  properly  dir 
minished  from  the  taffrail    down  each 


seam,  showing  the  round  of  the  taff- 
rail, and  differing  gradually  to  that  of 
tin-  arch-board;  by  planking  the  stern 
with  narrow  strakes,  we  may  be  able  to 
do  so  with  straight  plank  ;  tiny  may, 
and  doubtless  will  require  to  he  steam- 
ed. With  regard  to  the  shape  of  tin; 
tafferel,  little  can  be  said  that  would 
be  applicable  to  all  descriptions  of  ves- 
sels further  than  this  :  the  tafferel,  or 
whatever  finish  decorates  a  vessel,  or 
is  intended  to  do  so,  should  be  made 
to  correspond  with  the  vessel.  The 
idea  of  having  one  tafferel  mould,  or 
one  cut-water  mould  for  all  vessels,  no 
matter  what  the  form  may  be,  is  with- 
out a  foundation  in  the  philosophy  of 
Nature's  laws.  If  the  ships  are  alike  in 
form  and  finish,  it  is  then  not  out  of 
place  ;  but  if  the  models  differ,  all  other 
parts  should  be  made  to  correspond. 
Some  builders  have  labored  to  make  it 
appear  as  a  want  of  decision  of  char- 
acter in  the  man  who  would  not  build 
two  ships  alike,  but  would  adapt  his 
model  to  the  trade  of  the  ship,  even 
though  the  dimensions  were  the  same, 
or  nearly  the  same ;  to  us,  however, 
the  continued  sameness  which  stamps 
all  vessels  built  by  the  same  man,  is 
a  manifest  weakness,  and  admonishes 
us  that  the  man  has  but  one  idea  ;  in 
other  words,  that  he  can  only  icade, 
or  he  would  venture  into  deeper  water, 
and    be   governed,  to   some    extent  at 


3SS 


MARINE    AND    NAVAL    ARCHITECTURE. 


least,  by  circumstances.  If,  for  ex- 
ample, a  ship  be  longer  than  another 
of  the  same  model,  the  only  difference 
being  in  the  expansion  of  the  model, 
does  it  not  follow  that  the  head  and 
stern  should  also  be  expanded  ?  We 
are  persuaded  that  no  mechanic  would 
decide  against  us ;  and  yet  we  see  ship 
after  ship,  no  matter  what  the  size, 
with  the  same  sized  head  on  ;  it  is  not 
enough  to  rake,  raise  or  lower  a  cut- 
water mould,  and  say  that  all  is  right ! 
The  laws  of  proportion  apply  as  fully 
and  as  fairly  to  heads  and  sterns  as  to 
any  part  of  the  ship,  and  that  which 
was  designed  to  ornament  a  ship  is 
sometimes  made  to  disparage  her 
beauty  ;  neither  is  it  enough  to  say 
that  one  builder's  heads  and  sterns  are 
equal  or  superior  to  another,  or  to  any. 
We  say,  and  without  fear  of  successful 
contradiction,  that  every  ship's  head 
should  be  adapted  to  the  ship.  If  a 
ship  seems  to  require  a  long  head,  she 
requires  an  adaptation  aft  in  the  rake 
of  the  stern  ;  or  if  we  have  no  head,  we 
require  less  rake  to  the  stern  ;  another 
feature  with  regard  to  the  sterns  of 
ships :  they  are  made  to  appear  heavy 
by  their  continued  sameness  or  equality 
of  rake  ;  a  twist  to  the  stern  imparts  a 
life-like  appearance,  and  while  the  cor- 
ner of  the  stern  may,  for  appearance, 
have  all  the  rake  necessary,  the  centre 
may    have    less,    and    will    furnish"  a 


stronger  stern.  The  altitude  of  the 
arch-board  is  usually  determined  by 
the  size  of  the  rudder,  inasmuch  as  the 
counter  is  extended  above  the  stock  of 
the  rudder  at  least  one  of  the  strakes 
of  the  same ;  and  farther,  the  cabin 
windows  are  designed  to  furnish  light 
below  the  main  deck  beams,  which 
must  of  necessity  keep  them  down. 
The  practice  prevails  of  having  alter- 
nately every  second  window,  such  only 
in  appearance,  it  being  a  false  window  ; 
this  is  accomplished  by  rabbeting  the 
timbers  sufficiently  deep  to  receive 
plank  of  the  same  thickness  as  the 
stern,  and  sunk  back  Mush  with  the 
moulding  edge  of  the  timber  ;  this 
blank  surface  is  made  before  the  upper 
arch-strake  is  put  on,  which  covers 
enough  of  the  upper  part  of  this  false 
light  to  make  it  tight  with  light  calk- 
ing ;  the  same  may  be  said  with  refer- 
ence to  the  arch-board,  the  plank  form- 
ing the  false  light  extends  below  the 
upper  edge  of  the  arch-board  in  the 
same  manner  as  above  ;  the  vertical 
edges  that  rabbet  into  the  timber  are 
covered  with  the  pilaster  which  covers 
the  timber  ;  cabin  windows  on  the  stern 
are  usually  made  wider  than  their  depth 
on  the  face  of  the  stern,  inasmuch  as 
the  stern  is  broader  than  deep,  and  not 
only  so,  but  any  extension  above  the 
usual  depth  would  be  useless,  being  di- 
rectly in  range  of  the  first  beam  next 


( 


MARINE    AND    NAVAL    ARCHITECTURE. 


389 


to  the  stern.  The  beauty  of  this  part 
of  the  stern  consists  in  having  more 
round  to  the  stern  at  the  arch-board 
than  elsewhere  ;  also  to  have  the  upper 
and  lower  arch  taper  as  we  recede 
from  the  centre  ;  in  addition  to  this, 
the  width  of  the  windows  should  taper 
in  width,  and  the  pilaster  should  also 
be  reduced  as  we  approach  the  outside 
of  the  stern. 

Where  those  little  things  are  attend- 
ed to,  the  casual  observer  is  at  once 
struck  with  the  symmetry  that  is  exhibi- 
ted, and  is  pleased  with  the  appearance, 
but  cannot  tell  why  ;  there  is  a  certain 
something  that  makes  an  impression 
on  his  mind  ;  in  other  words,  he  has 
seen  proportion  somewhere,  and  if  no- 
where else,  he  has  seen  it  in  the  look- 
ing-glass when  recognizing  his  own 
person  ;  and  now  he  sees  the  same 
trait,  viz.,  proportion  reflected  back, 
and  he  at  once  recognizes  it.  It  would 
be  the  same  with  any  other  piece  of 
mechanism,  a  house,  a  church,  or  even 
a  barn  ;  and  if  the  casual  observer  can 
appreciate  proportions,  how  they  must 
loom  up  to  the  man  with  a  cultivated 
eye,  who  has  taken  Nature  for  his 
model,  and  has  adhered  to  that  model 
with  unfaltering  fidelity  ! 

As  we  have  before  remarked,  we 
can  give  no  stereotyped  dimensions 
that  will  apply  to  any  vessel;  we  may 
and  shall  give  an  outline  that  has,  or 


does  look  well  on  a  certain  ship,  but  it 
does  not  follow  that  the  same  will  ap- 
ply to  any  other  ship  ;  and  although 
many  have  deemed  it  the  part  of  weak- 
ness to  be  changing,  we  deem  it  quite 
the  reverse ;  no  one  would  suppose 
that  it  was  an  exhibition  of  folly  to  re- 
quire the  tailor  to  make  a  coat  fit  in 
every  part ;  and  although  the  reader 
may  weigh  precisely  the  same,  and  be 
exactly  of  the  same  height  as  his  friend, 
yet  he  would  rather  the  tailor  should 
measure  himself  than  his  friend  for  the 
coat  he  was  about  to  make  for  him, 
and  why  ?  simply  because  he  thinks  it 
will  fit  better;  so  we  say  of  ships  with 
this  qualification. 

We  will  now  do  what  we  promised. 
The  arch-board  for  a  ship  of  1000 
tons  may  be  about  13  inches  at  the 
centre,  and  11  to  11 J  at  the  ends;  the 
upper  arch  may  be  about  18  inches 
above  the  lower  one  at  the  centre,  and 
164  to  17  at  the  outer  window;  if  we 
prefer  a  window  in  the  centre,  it  must 
be  a  false  one,  on  account  of  the  rud- 
der, and  may  be  2  feet  wide,  both  above 
and  below,  joined  by  a  pilaster  on  each 
side  ;  these  pilasters  may  be  1  foot 
wide  and  parallel;  the  next  window  on 
each  side  may  be  2H  below,  and  211 
above,  followed  by  pilasters  111  below, 
and  llf  above  ;  the  next  two  windows, 
one  on  each  side,  may  be  2H  below, 
and  20i  inches  above,  followed  by  two 


390 


MARINE    AND    NAVAL    ARCHITECTURE. 


pilasters  Hi  below,  and  Hi  above; 
we  now  have  5  windows  ;  the  next  two 
may  be  20i  inches  below,  and  19s 
above  ;  thus  it  will  be  seen  that  we 
make  the  taper  greater  as  we  approach 
the  outer  window.  With  regard  to 
the  number  of  windows,  the  width  and 
shape  of  the  stern  will  determine  this; 
neither  can  the  tafferel  be  delineated ; 
it  may  land  on  the  arch-board,  as  it 
has  almost  from  time  immemorial,  or 
may  be  conducted  around  the  quarter, 
and  under  the  arch-board,  any  way  in 
which  it  will  best  lit  the  stern.  We 
have  shown  two  modes,  the  one  on 
Plate  9,  where  there  is  no  counter, 
and  the  wood  ends  run  up  to  the  lower 
edge  of  the  arch-board,  and  lights  are 
inserted  instead  of  windows,  which  are 
preferable ;  these  lights  are  weather- 
proof, and  are  more  secure  ;  they  are 
hung  with  hinges,  and  closed  with  a 
hand  screw  to  exclude  the  weather. 
The  second,  Plate  10,  shows  an  easy 
quarter,  with  lights  instead  of  windows, 
and  the  tafferel  turned  under  with 
counter,  but  no  arch-board  ;  a  single 
moulding  continues  the  upper  wale 
across  the  stern.  A  mechanic  will  at 
once  discover  that  the  old  stereotyped 
tafferel  would  not  and  could  not  be 
made  to  appear  well  on  a  stern  in  the 
form  of  Plate  10  ;  and  who  will  take 
the  responsibility  of  asserting  that  this, 
or  that  of  Plate  9,  are  not  better  cal- 


culated for  every  necessary  sea  quality 
than  the  old-fashioned  stern  ? 

There  was  a  time  when  a  merchant 
ship  must  have  quarter  galleries,  to 
give  a  majestic,  warlike  appearance, 
inasmuch  as  this,  with  every  thing  else 
copied  from  the  Navy,  must  be  right  : 
few  dared  to  call  in  question  the  pro- 
priety of  the  addition  ;  and  to  the  pres- 
ent time  some  English  merchant  ships 
have  quarter  galleries. 

The  day  has  gone  by  when  the  Navy 
will  be  taken  for  a  pattern  in  any 
branch  of  commercial  operations.  In- 
dividual enterprise  must  furnish  a  basis 
for  naval  operations  in  ship-building, 
unless  its  improvements  are  in  future 
more  rapid  than  they  have  been.  We 
want  the  quarter  reduced  to  its  lowest 
possible  dimension  or  size,  for  the  bene- 
fit of  the  ship,  in  order  to  equalize  the 
lines  of  flotation. 

With  this  general  description  of 
sterns,  and  the  manner  of  building 
them,  we  leave  this  end  of  the  ship, 
and  go  forward  on  the  head  :  this,  like 
the  stern,  should  be  adapted  to  the 
form  of  the  ship  ;  the  whole  bow  and 
rake  of  the  stern  should  determine  its 
size  and  form.  The  head  may  be  laid  . 
down  with  the  ship,  as  we  have  shown, 
but  the  practice  is  quite  common  of 
making  a  mould  on  the  ship  about  the 
time  the  ship  has  her  decks  framed, 
ceiling  in,  and    wales,  on  ;   this  is  the 


' 


- 


MARINE  AND  NAVAL  ARCHITECTURE, 


391 


most  suitable  time,  inasmuch  as  the 
head  cannot  be  finished  much  before 
the  ship  is  ready  to  launch  ;  and  yet 
there  is  time  enough  to  finish  the  head 
if  it  should  not  be  commenced  until 
the  vessel  is  planked  ;  there  is  this  ob- 
jection to  delay  :  the  carver  must  or 
should  have  all  the  time  that  can  well 
be  allowed,  (unless  they  have  time  on 
their  hands ;)  the  head  cannot  be  set 
until  the  hawse-holes  can  be  located. 
A  surface  of  boards  is  extended  beyond 
the  stem  to  the  extent  we  design  the 
cut-water  shall  be  ;  upon  this  crude 
mould  battens  are  tacked  to  represent 
the  front  of  tiie  cut-water  and  the 
cheeks,  and  when  they  conform  to  the 
eye,  they  are  marked,  and  the  mould 
taken  down,  not  however,  before  it  is 
fully  determined  whether  the  head  rail 
shall  blend  into  the  plank-sheer  mould- 
ing, or  continue  in  that  direction  for  a 
suitable  distance,  and  then  suddenly 
turn  and  conform  to  the  size  and  di- 
rection of  the  cat-head  ;  this  is  a  mat- 
ter of  taste  with  the  builder.  There 
appears  in  our  minds  to  be  but  one 
objection  to  the  head  rail  uniting  with 
the  cat-head,  which  is  its  consequent 
increased  size  at  the  after  end,  which 
imparts  a  heavy  appearance  to  the 
whole  bow  ;  the  head  rail  starting  from 
the  same  point,  viz.,  the  figure  head, 
should  not  be  larger  than  the  cheeks 
at  the  starting  point,  which  they  must 


of  necessity  be  when  it  is  designed  to 
end  at  the  cat-head  ;  much,  however, 
of  this  heavy  appearance  may  be  re- 
moved by  the  taper  of  the  checks  and 
head  rail.  Suppose  the  head  rail  to 
be  moulded  four  inches  at  the  figure, 
and  twelve  at  the  cat-head,  it  follows 
that  the  usual  taper  would  be  eight 
inches  at  the  centre  ;  this  would  im- 
part the  heavy  appearance  of  which 
we  complain  ;  six  and  three-quarters 
to  seven  inches  is  all  that  is  required  ; 
and  if  the  strength  is  deemed  insuffi- 
cient, it  may  be  increased  beyond  the 
regular  taper  in  the  siding  direction. 
With  regard  to  the  cheeks,  they  should 
swell  beyond  the  regular  taper,  inas- 
much as  their  size  is  not  commensu- 
rate with  their  length  ;  their  strength 
is  secured  in  the  transverse  direction, 
for  we  discover  that  at  the  figure  they 
are  but  \\  inches  ;  while  at  the  wood 
ends,  if  the  line  were  continued  across 
the  throat  of  the  knee,  they  would  be 
12  inches  or  more  ;  again  in  the  siding- 
direction  they  may  be  2}  inches  at  the 
figure,  and  61  to  7  inches  on  the  bow  ; 
what  we  mean  in  the  taper  of  the 
cheeks  is,  that  half  way  between  the 
figure  and  the  bow,  the  cheek  should 
be  moulded,  or  show  in  the  vertical  di- 
rection more  than  half  of  the  difference 
between  the  two  terminations:  that  is 
to  say,  if  the  bracket  or  following  piece 
of  the    cheek  were  2>   inches  at    the 


■ 


392 


MARINE    AND    NAVAL    ARCHITECTURE. 


figure,  and  6j  at  the  bow,  it  should  be 
at  least  42  inches  to  41  at  the  middle 
of  length,  instead  of  41,  which  would 
be  the  regular  taper  ;  by  thus  relieving 
the  one  of  the  extra  heavy  appearance, 
and  the  other  of  its  consequent  (when 
contrasted)  light  appearance,  we  ap- 
proximate that  symmetry  so  essential 
in  the  appearance  of  a  vessel's  head ; 
one  quarter  of  an  inch  seems  to  cover 
but  a  small  space  in  the  eye  when  look- 
ing at  a  ship's  head,  but  even  that  may 
be  seen  readily,  and  may  be  added  to 
or  taken  from  the  cheeks  or  head  rail, 
and  be  noticeable  at  the  first  glance  of 
the  practised  eye  ;  the  difficulty  with 
many  mechanics  lies  just  here  :  they 
cannot  determine  when  the  form  is 
right,  or  detect  error  in  adaptation  of 
the  one  to  the  other ;  they  have  be- 
come so  accustomed  to  let  others  do 
their  thinking,  that  they  find  it  difficult 
to  think  for  themselves. 

There  is  a  certain  fitness  about  the 
head  of  a  ship  that  at  once  stamps  an 
impression  on  the  mind  in  relation  to 
the  entire  ship,  and  why  ?  We  say 
that  the  head  of  a  ship  is  like  a  por- 
trait, we  look  at  the  physiognomy  of 
the  man,  and  judge  of  his  intellectual 
endowments — of  his  internal  and  his 
external  qualities  ;  so  with  the  ship,  it 
is   the  builder's   mechanical   portrait  ; 


certain  ships  merely  on  account  of  the 
peculiar  symmetry  of  the  head  or  stern. 

It  is  designed  as  an  ornament  to  de- 
corate the  representative  of  a  thing  of 
life,  and  any  thing  that  would  in  the 
least  mar  its  beauteous  proportions, 
should  be  studiously  avoided. 

It  was  formerly  the  custom  to  keep 
both  of  the  cheek  knees  below  the 
hawse-holes,  but  of  late  years  the  prac- 
tice has  grown  obsolete,  and  the  hawse- 
holes  come  between  the  cheeks,  and 
the  improved  appearance  is  quite 
manifest. 

It  may  not  be  out  of  place  to  show 
the  only  correct  way  to  side  cheek 
knees,  although  it  may  be  thought  by 
some  that  this  operation  is  so  generally 
understood,  that  it  would  be  entirely 
superfluous;  we,  however,  think  quite 
differently.  There  are  very  few,  even 
among  those  who  do  little  else  besides  set 
heads  and  sterns,  who  can  side  a  cheek 
knee  properly,  and  we  have  seen  heads 
greatly  depreciated  in  their  appear- 
ance, in  consequence  of  a  discrepancy 
in  this  particular.  It  must  be  quite 
apparent,  that  whatever  of  the  knees 
extends  beyond  the  wood  ends  towan 
the  stern,  should  be  of  the  same  size 
as  that  at  the  wood  ends ;  and  that  on 
the  sharp  vessel,  if  the  after  end  of  the 
knee  or  the  end   of  the  body  extends 


and    curiosity  or  quest   of  knowledge  j  farther  aft  than  the  corner  at  the  wood 
has   often   attracted  men  on  board   of  ends,  it  should  be  sided    by  the  upper 


HOWLAND     SC 


■ 


MARINE    AND    NAVAL    ARCHITECTURE 


393 


edge  of  the  mould,  because  the  lower 
side  is  continued  parallel  on  the  bow; 
most  persons   continue  the    mould  no 
farther    than    the    corner,    when   they 
mould  the  arm,  or  the  part  that  comes 
against  the  cut-water,  and  then  obtain 
a     spot     through     the     throat,    wind- 
ing  out  the  rest   of  the   face  by  this 
spot.      This  is  manifestly  wrong,  as  will 
appear    upon    a    moment's    reflection. 
Who  can  tell  at   what  angle  this  spot 
must   be   obtained  in    the  throat  ?     If 
the  cheek  knee  be  out  square,  which  it 
undoubtedly   would,  let  the  mould  ex- 
tend beyond    the  corner  at   the  wood 
ends,  and  as  much  farther  as  will  bring 
the  end  of  the  mould  and  the  end  of 
the  body  of  the  knee  on  the  bow  in  a 
line  square  from  the  arm   against  the 
cut-water  ;  this  of  course  comprehends 
a   square  knee,  and  then  the  secret  is 
all  out ;  let  the  spots  be  put  on  parallel 
to  this  line,  or  put  a  spot  on  the  knee 
that  shall  be  parallel  to  this  line,  and 
at  the  same  time  having  one  edge  of 
the   straight  edge  on  the  mould  when 
the  spot  is  obtained  ;   this  is  what  we 
require   of  the    mould   for   siding  the 
knee  ;  after  having  marked  by  its  edges 
on  the  arm  the  size  of  the  same,  it  will 
readily  be  perceived  that  the  remaining 
spots  may  be  pricked  oft",  being  parallel 
and  out  of  wind  with  the  first,  and  thus 
the  knee  may  be  counter-moulded,  and 
will  look  fair  from  more  than  one  posi- 


tion ;  it  will  appear  fair  from  any  view 
we  may  take.  The  space  between  the 
cheeks  will  also  have  a  proportionate 
taper,  likewise  the  opening  between 
the  cheeks  and  rail ;  the  space  or  mar- 
gin of  the  cut-water  must  be  looked 
at ;  that  is,  the  surface  between  the 
edge  of  the  cut-water  and  the  lower 
cheek  ;  in  a  word,  all  must  be  seen  at 
the  first  glance ;  hence  we  would  al- 
ways recommend  that  a  draft  be  drawn, 
which  costs  less  in  time  than  to  go 
through  the  operation  we  have  de- 
scribed, besides  having  just  what  we 
want.  The  sheer-plan  should  be  drawn, 
in  order  that  we  may  adapt  the  head 
to  the  ship. 

We  would  not  tenaciously  adhere  to  the 
ordinary  cut-water,  cheeks,  and  head 
rail,  by  any  means;  there  are  ships  upon 
which  they  cannot  be  made  to  appear 
well,  and  upon  which  the  plain  bow,  if 
extended  out  to  a  point,  would  make  the 
best  finish  that  could  be  made.  It  is 
more  difficult  to  set  the  full  figure  on  a 
cut-water  that  shall  appear  graceful, 
than  the  billet  head  or  simple  scroll ; 
the  reason  is  found  in  the  difficulty  in 
getting  the  bow-sprit  high  enough,  and 
if  the  head  is  extended  far  enough  to 
obtain  the  height  we  require,  we  have 
the  cut-water  farther  out  than  we  wish. 
The  reason  why  the  bow-sprit  may  not 
be  raised  above  the  ordinary  height 
will  appear  obvious,  if  we  but  reflect 


50 


394 


MARINE    AND    NAVAL    ARCHITECTURE 


tlnit  it  requires  some  security  above  to 
counteract  the  leverage  on  the  bow; 
the  bow-sprit  should  in  all  eases  have 
a  breast-hook  or  chock  above  to  con- 
fine the  bow  together. 

In  delineating  a  ship's  head,  either 
on  paper,  in  the  mould  loft,  or  on  the 
ship,  provision  should  be  made  for  the 
security  of  the  bob-stays  ;  the  head  rail 
should  be  made  to  clear  the  bow-sprit 
shrouds  ;  in  a  word,  the  whole  effort 
of  the  head  should  be  that  of  harmoniz- 
ing all  parts — no  chafing.  We  some- 
times see  a  ships's  bob-stay  braced  oft* 
from  the  cut-water  above  its  connec- 
tion, in  order  to  prevent  its  chafing  the 
head  ;  this  at  once  exhibits  a  lack  some- 
where, and  would  be  seen  by  a  man  of 
taste,  as  soon  and  as  far  as  he  could 
delineate  one  stay  from  another.  In 
smaller  vessels  it  would  be  difficult  to 
delineate  any  determinate  size  or  pro- 
portion for  the  heads  of  coasting  ves- 
sels, or  those  adapted  to  the  navigation 
of  our  rivers,  inasmuch  as  an  almost 
endless  variety  exists  in  model  and  de- 
scription, and,  consequently,  in  finish  ; 
in  very  many  instances  our  coasting 
and  river  vessels  would  look  much  bet- 
ter without  a  head  than  with  one  ;  but 
the  eye  of  the  owner  having  become 
familiarized  with  its  appearance,  sees 
nothing  amiss. 

Having  concluded   our    expositions 
on  the  heads  and  sterns,  after  having 


delineated  the  general  principles  of 
construction  sufficiently  lucid  for  the 
mechanic  of  ordinary  mind,  who  is 
willing  to  take  the  trouble  to  think,  we 
shall,  before  entering  upon  the  subject 
of  sparring  ships  and  other  vessels, 
make  some  tangible  remarks  upon 
launching  vessels,  and  thus  set  the  fab- 
ric afloat  after  its  construction,  and 
before  we  spread  the  canvass  to  the 
breeze. 

The  casual  observer  when  attending 
a  launch  is  instinctively  impressed  with 
the  idea  that  there  is  great  danger  of 
the  ship  falling  over  side-ways  out  of 
the  cradle,  or  the  bed  upon  which  she 
rests, as  soon  as  the  shores  are  removed; 
this  opinion  is  without  foundation,  in- 
asmuch as  the  centre  of  weight  must 
of  necessity  be  located  at  the  centre  of 
the  vessel  transversely.  To  illustrate 
this,  suppose  a  ship  weighing  when 
ready  to  launch  1000  tons,  and  that 
she  were  of  equal  density  throughout  ; 
we  will  also  assume  that  the  ship  was 
40  feet  wide,  and  was  prepared  for 
launching  in  a  cradle  of  13  feet  wide, 
that  being  a  trifle  less  than  one-third 
of  the  breadth  ;  we  now  have  25  tons 
of  weight  for  each  foot  of  breadth  ;  now 
is  it  not  plain,  that  if  the  keel  were 
sided  16  inches,  that  there  must  be  a 
leverage  equal  to  16f  tons  at  each  side 
of  the  k^el,  which  should  at  once  teach 
us  that  a  ship  would  stand  on  her  keel 


MARINE    AND    NAVAL    ARCHITECTURE. 


395 


alone,  without  a  shore  under  her,  pro- 
vided the  weight  of  materials  were  dis- 
tributed equally  on  eaeh  side  of  the 
centre  of  the  ship  ;  but  let  us  continue 
this  leverage  farther  :  we  have  assumed 
the  cradle  to  be  13  feet,  which  fur- 
nishes an  excess  of  weight  equal  to 
162  tons  ;  that  is  to  say,  that  it  would 
require  a  weight  equal  to  162  tons 
placed  6j  feet  outside  of  the  ways  to 
cause  an  equipoise,  or  a  liability  to 
cant  her  transversely  out  of  her  cra- 
dle ;  hence  we  discover  that  it  requires 
but  reflection  to  show  us  that  our  fears 
are  groundless.  With  regard  to  the 
width  of  the  cradle,  the  narrower  the 
better  for  the  ship,  but  at  the  same 
time  men  must  have  room  to  work  in 
getting  out  the  blocks. 

The  reasons  why  a  narrow  cradle  is 
best,  may  be  found  in  the  fact  that  upon 
the  centre  of  the  vessel  the  most  of  the 
weight  is  sustained,  inasmuch  as  the 
decks  are  kept  their  proper  distance 
above  the  keel  and  keelson  by  the 
stanchions,  and  the  entire  ship  would 
be  sustained  on  the  keel  with  less 
strain  to  the  structure,  than  at  any 
other  point  ;  it  then  follows  that  the 
ways  should  be  as  near  as  may  be,  all 
things  else  considered — one  third  of  the 
breadth  of  the  vessel  has  been  consid- 
ered as  a  rule  ;  but  we  know  of  no  rea- 
son why  it  should  be  followed;  if  li 
feet  furnish    room   enough  to  remove 


the  blocks  when  launching  a  ship  of 
40  feet  beam,  we  cannot  discover  any 
reason  why  they  do  not  furnish  enough 
to  do  the  same  work  for  a  ship  of  50 
feet  beam  ;  the  width  of  the  cradle  is 
considered  to  be  the  distance  between 
the  outside  of  the  ways. 

With  regard  to  the  angle  of  descent 
for  launching,  it  may  only  be  necessary 
to  say,  that  the  weight  of  the  vessel, 
and  the  surface  of  bilge  ways,  should 
influence  us  in  this  particular;  if  the 
vessel  to  be  launched  be  a  ship,  1  inch 
or  1J  inches  to  each  foot  of  length  will 
be  quite  sufficient  ;  if  the  ship  be  very 
large  and  heavy,  i  of  an  inch  to  eaeh 
foot  of  length  is  an  abundance,  and  even 
less  will  do  ;  £  has  been  found  to  an- 
swer every  purpose,  but  for  long  steam- 
boats, intended  for  river  navigation,  1 
inch  to  each  foot  would  be  not  any  too 
much  ;  in  such  cases  the  ways  should 
not  be  wide,  inasmuch  as  the  surface 
of  ways  and  the  weight  of  the  boat  do 
not  correspond  ;  the  boat  being  very 
light,  will  not  counteract  the  glutinous 
properties  of  the  tallow,  (the  substance 
commonly  used  for  greasing  the  ways  ;) 
in  such,  and  indeed  in  all  cases.  Castile 
soap  should  be  used  ;  1  part  of  Castile 
soap  to  2  of  tallow  is  a  fair  propor- 
tion, and  will  prove  an  ample  remunera- 
tion for  the  extra  expense  consequent 
upon  its  use.  The  ground  ways  should 
be  arched  where  we  may  not  be  able  to 


596 


MARINE    AND    NAVAL    ARCHITECTURE 


obtain  all  the  descent  we  require  ;  the 
curve  should  be  regular — not  more  in 
one  part  of  the  length  than  in  another  ; 
the  blocks  under  the  ways  may  be  spaced 
as  the  keel  blocks  are  forward,  but  they 
should  be  somewhat  closer  aft  ;  the 
ways  may  cant  inward,  in  proportion 
to  the  angle  of  dead  rise  ;  there  can 
be  no  determinate  rule  for  this ;  it  is 
only  requisite  to  have  enough  to  pre- 
vent the  packing  midship  from  having 
too  much  drift,  and  to  prevent  the  bilge 
way  from  inclining  outward,  which  it 
undoubtedly  would  do,  (and  sometimes 
does;)  1  inch  to  the  foot  of  breadth  is 
enough  cant  for  the  ways ;  they  should 
be  spaced  somewhat  farther  apart  at 
the  lower  end  than  at  the  stem — from 
3  to  4  inches  is  as  much  as  is  usual, 
unless  the  length  of  ways  be  very  great, 
or  much  more  than  is  usual.  It  has 
been  customary  to  keep  the  outer  edge 
of  the  ways  fair,  and  spike  a  ribband 
on,  extending  above  the  surface  of  the 
ways  some  3  inches  their  entire  length  ; 
against  this  ribband  shores  are  distri- 
buted from  10  to  15  feet  apart;  the 
heels  secured  against  stakes  in  the 
ground,  and  the  heads  spiked  into  the 
ribband.  Some  builders  prefer  the 
mode  introduced  in  this  city  by  the 
late  Isaac  Webb :  by  this  mode  the 
ribband  is  secured  to  the  bilge  way, 
and  the  inside  of  the  ground  way  is 
kept  fair  and  straight ;  the  shores  com- 


ing against  the  way.     By  this  mode  it 
will  be  perceived  that  there  is  no. more 
ribband    required   than   the  length   of 
each  bilge  way,  and  we  have  the  sur- 
face of  the  way  exposed  to  view.     It 
will  also  be  perceived  that  below  the 
edge  of  the  bilge  way  the  ribband  ex- 
tends the  same  as  in  the  former  case, 
but  a  remark  seems  necessary  here  :  in 
relation  to  the  strength  of  the  ribband 
when   on  the  bilge,  there  should  be   a 
great  amount  of  strength  in  the  timber 
itself,  inasmuch  as  no  amount  of  fast- 
ening that  could  be  put   into  the  rib- 
band and  bilge  way,  would  compensate 
for  tjiis  when  the   bilge   way  inclines 
out ;  the  ribband    must  be   sufficient- 
ly strong    in    itself  to  keep  the    way 
inboard  ;  hence    we   say  the    ribband 
should   be  of  oak,  and  thick,  such  as 
will  not  readily  split ;  to  prevent  which, 
fastening  should  be  put  through  it  edge- 
wise; there  is  no  liability  to  splitting  off' 
the  ribband  when  outside,  inasmuch  as 
the  shores  come  against  it  above  the 
face    of  the    ground    way,    which  ef- 
fectually prevents   any   accident  from    . 
this  source.      There  is  little  danger  to 
be  apprehended  from  the  starting    of 
the  ribband  when  either  mode  is  adopt- 
ed, provided  the  vessel  is  lively  on  the 
ways,  and  starts  as  soon  or  before  the 
blocks  are  all  removed ;  the  custom  of 
holding  the  vessel  until  all  the  bloc' 
are    out,    is    wrong;    when    the 'keel 


01 


v« 


MARINE  AND  NAVAL  ARCHITECTURE. 


397 


blocks  are  removed,  they  are  taken  out 
aft  first,  and  the  shores  at  the  same  time, 
or  in  advancee  of  the  work  as  it  pro- 
gresses from  aft  ;  and  before  two-thirds 
of  the  blocks  are  out,  the  shores  should 
be  all  out  ;  the  vessel  hangs  aft  as  the 
ways  take  her  weight,  and  often  cants 
a  number  of  the  blocks.  If,  however, 
she  is  not  inclined  to  go  when  the 
blocks  are  all  out,  a  battering  ram  or 
screw  may  be  used  ;  if  a  screw  is 
placed  against  the  end  of  the  bilge  way, 
there  may  be  a  strain  put  on  it  before 
the  blocks  are  all  out,  and  as  the  re- 
moving of  the  blocks  advances  towards 
completion,  the  strain  may  be  increased 
on  the  screw;  sometimes  when  a  ves- 
sel is  launched  on  tallow  after  being 
packed  up  several  days,  it  is  found 
very  difficult  to  start  her,  and  it  has 
often  occurred  that  the  vessel  of  neces- 
sity was  blocked  and  shored  up  again, 
the  packing  removed,  and  the  ways 
regreased.  In  such  cases,  it  has 
been  found  that  the  tnllow  has  been 
so  completely  packed  into  a  cake  that 
it  had  no  appearance  of  having  the 
H???$r  slippery  property  ;  in  other  cases, 
when  the  weather  has  been  hot,  the 
tallow  was  melted,  and  to  a  great  ex- 
tent disappeared  ;  hence  we  say,  that 
Cast'rlf  soap  should  be  used.  In  the 
Hteavy,  the  packing  is  all  lit  ted  on  the 
v  dry  ways,  and  then  removed,  and  the 
wa^J*  greased  ;  a*d  when  it  is  designed 


to  let  a  vessel  stand  on  the  ways,  and 
wait  for  orders,  as  is  the  case  in  the 
Navy,  it  is  the  proper  mode,  but  if  we 
are  to  launch  as  soon  as  ready,  it  is  not 
necessary ;  neither  is  it  necessary  to 
hold  the  ship  by  bolting  the  bilge  way, 
and  sawing  it  off;  (when  for  this  rea- 
son, which  is  sufficient,  were  there  no 
other  :)  if  the  ship  has  an  inclination  to 
go,  we  hold  her  ;  if  she  has  no  inclina- 
tion, we  hinder  her ;  and  when  the 
ways  are  bolted,  we  cannot  know  until 
the  blocks  are  out,  or  the  ways  are 
sawed  off,  and  then  there  has  been  . 
time  lost ;  not  that  we  suppose  there 
is  danger  of  her  coming  down,  or  get- 
ting out  of  the  cradle,  but  of  the  tallow 
packing  hard  ;  the  ship  should  be  live- 
ly ;  that  is,  have  a  little  motion,  which 
keeps  the  tallow  slippery. 

With  regard  to  the  packing  at  the 
ends  of  the  vessel,  a  ribband  extends 
across  the  poppets,  over  which  chains 
are  extended  that  go  under  the  keel 
and  up  the  opposite  side  ;  these  being 
wedged  taut,  support  the  ends  of 
the  vessel ;  sometimes  cleets  are  spiked 
above  the  heads,  but  this  is  manifestly 
wrong,  particularly  on  the  bow  ;  we 
have  seen  a  fore  wood  broke;  entirely 
off  by  a  set  bolt  placed  over  a  elect 
that  was  spiked  on  the  bow. 

When  those  poppets  reach  the 
after  end  of  the  ways,  the  sooner  they 
get  out  of  their  place  the  better,  pro- 


39S 


MARINE   AND    NAVAL    ARCHITECTURE. 


vided  there  is  water  enough  for  the 
bow  to  drop;  and  it*  there  is  not,  they 
can  be  held  better  by  chains  ;  there 
may  be  two  ribbands,  one  at  the  heel, 
and  another  at  the  head  ;  but  when 
this  is  the  case,  the  poppets  should 
incline  a  very  considerable  inboard  to- 
wards the  centre  from  a  perpendicular 
line  at  the  head  :  it  is  not  absolutely 
necessary  that  the  heads  of  the  poppets 
should  be  as  far  apart  on  the  two  sides 
at  the  head,  as  the  packing  midship  ; 
in  other  words,  that  the  cradle  the  ship 
l  sets  in,  should  be  as  wide  at  the  ends 
as  in  the  centre  ;  besides,  the  poppets 
will  hold  up  much  more  without  the 
least  slip  when  the  heads  are  tumbled 
home. 

The  principal  difficulty  in  launching 
long  steamboats  is  found  in  the  differ- 
ence in  the  descent  of  the  boat  and  the 
ways — the  boat  standing  at  a  much 
smaller  descent  than  the  ways,  the 
fore  end  of  the  ways  are  against  the 
bow.  When  we  find  that  we  have  not 
as  much  descent  as  we  desire,  we 
may  let  the  mean  descent  be  all,  or  a 
lit  lie  more  than  we  require,  and  arch 
the  ways,  so  that  the  after  ends  will 
have,  say  li  or  li  inches  to  the  foot, 
and  the  fore  end  *,  f  or  f  of  an  inch — 
the  circumstances  of  the  case  deter- 
mining the  amount  in  all  cases  ;  it  is 
better  to  have  a  little  more  descent 
than    is    necessary,    than     not     quite 


enough  ;  in  the  one  case  we  have  a 
good  launch — in  the  other  we  have 
none  ;  we  are  quite  safe  in  saying  that 
any  vessel  will  go  at  1J  inch  to  the  foot, 
and  this  is  usually  considered  enough 
when  both  the  ground  and  bilge  ways 
are  yellow  pine,  and  have  been  used  a 
few  times  ;  care  should  be  taken  that 
there  is  the  same  space  or  more  for 
the  fore  foot  to  pass  than  its  extension 
below  the  ways  at  the  bow,  else  she 
may  drag  on  the  shore  in  passing  out 
of  the  slip. 

We  shall  assume  that  the  ship  is 
launched,  and  along  side  of  the  wharf, 
ready  for  her  spars,  and  we  now  enter 
upon  the  duty  of  delineating  the  man- 
ner of  adapting  the  spars  to  the  ship. 
The  various  random  modes  of  sparring 
vessels  in  all  parts  of  the  world  have 
rendered  this  the  most  difficult  and 
perplexing  problem  that  has  ever  en- 
gaged the  attention  of  commercial 
men  ;  and  so  fairly  and  fully  has  the 
labor  of  devising  an  unvarying  rule  for 
masting  and  sparring  ships  and  other 
vessels  been  divided,  that  there  are  al- 
most as  many  rules  as  there  are  builders': 
each  has  carved  out  his  own  path,  and 
each  adheres  with  tenacity  to  his  own 
darling  project,  which  in  ninety-nine 
cases  out  of  every  hundred,  has  no  re- 
ference to  the  peculiarities  of  the  ves- 
sel. Perhaps  there  is  no  branch  of 
human  knowledge  that  is  kept  so  cem- 


MARINE    AND    NAVAL    ARCHITECTURE. 


399 


pletely,  so  promptly  within  the  pre- 
cincts of  the  mind  as  the  little  that  is 
known  of  what  pertains  to  the  science 
of  sparring  vessels. 

The  most  remarkable  feature  con- 
nected with  this  whole  subject  of  spar- 
ring vessels,  is  the  fact  that  men  have 
not  dared  to  give  utterance  to  a  single 
thought  that  would  tend  to  show  the 
absurdity  of  the  present,  course. 

We  shall  endeavor  first  to  show  what 
are  the  most  prominent  rules  in  some 
parts  of  Europe,  where,  as  in  the  Uni- 
ted States,  no  reference  is  had  to  the 
peculiarities  of  the  model  presented  by 
the  exterior  surface  of  the  vessel  to 
the  fluid,  from  which  is  received  all 
the  absolute  resistance  that  is  to  be 
overcome.  We  unhesitatingly  say, 
that  the  annals  of  scientific  knowledge 
does  not  furnish  a  parallel  for  absur- 
dity :  a  ship  is  pronounced  a  bad  or 
good  model  in  the  ratio  of  her  perform- 
ance, be  it  what  it  may,  without  the 
most  remote  reference  to  the  location 
of  the  centre  of  buoyancy,  or  to  the 
centre  of  effort  of  the  sails  ;  in  this 
particular,  mechanics  have  all  become 
sailors,  continually  looking  aloft  in  the 
aerial  regions  for  what  can  only  be 
found  beneath  the  surface  of  the  water. 
It  requires  but  a  moment's  reflection 
by  the  thinking  man,  to  discover  that  the 
longitudinal  centre  of  the  lateral  resist- 
ance must  of  necessity  be  the  fulcrum, 


each  side  of  which  the  sail  should  be 
about  equally  balanced, allowance  being 
made  for  certain  contingencies,  found 
principally  in  coasting  vessels. 

Force  operates  the  same,  whether 
it  be  that  of  the  hand  against  the  bow 
or  stern  of  a  vessel,  or  an  equal  amount 
in  wind  against  the  sail;  the  masts  of 
vessels  are  like  so  many  levers,  and  al- 
though the  power  is  distributed  along 
the  mast  in  the  ratio  of  the  altitude 
each  sail  having  a  different  size,  con- 
sequent upon  a  separate  location,  yet 
the  centre  of  the  propulsory  power 
of  each  sail  is  the  point  at  which  the 
effect  takes  place  ;  hence  it  follows 
that  there  must  be  a  point  that  repre- 
sents the  force  of  all  the  sails,  that 
point  we  have  already  denominated 
the  centre  of  propulsion  ;  it  then  only 
remains  to  determine  where  this  point 
should  be  located,  and  the  universal 
dissolvent  to  this  mysterious  problem 
has  been  discovered.  We  should  re- 
member that  we  not  only  require  its 
longitudinal  location,  but  we  require 
its  altitude.  In  order  that  we  may 
more  fully  understand  the  subject,  it 
will  not  be  amiss  to  examine  the  con- 
sequences of  having  an  improper  loca- 
tion ;  first,  if  the  centre  of  propulsion 
is  too  high,  and  the  vessel  is  sailing  be- 
fore the  wind,  she  will  incline  by  the 
head,  and  her  speed  will  be  impaired  : 
if  the  centre  of  propulsion  be  too  low, 


400 


.MARINE    AND    NAVAL    ARCHITECTURE. 


the  vessel  will  incline  by  the  stern ; 
this  seems  paradoxical,  but  is  neverthe- 
less true ;  and  the  reason  is  found  in 
the  fact  that  the  bow  is  entering  strong 
water,  or  water  possessing  its  full  share 
of  buoyancy,  and  the  pressure  against 
the  bow  being  at  right  angles  with  the 
surface  of  the  fluid,  imparts  a  lifting 
tendency  to  the  bow,  and,  as  a  conse- 
quence, the  stern  must  go  down,  inas- 
much as  the  centre  of  propulsion  is 
not  high  enough  to  counteract  it  ; 
hence  one  of  the  reasons  why  ships  do 
not  perform  in  accordance  with  the 
wishes  of  those  who  command  them  ; 
a  tolerable  good  model  is  often  repudia- 
ted in  consequence  of  this  mal-distri- 
bution  of  power.  The  effects  of  this 
unequal  distribution  is  also  seen  when 
sailing  on  the  wind  ;  if  the  centre  of 
propulsion  be  too  far  forward,  she  will 
not  come  to  the  wind  readily,  and  what 
has  been  termed  the  lee  helm  will  fol- 
low ;  and  on  the  other  hand,  if  the 
centre  of  propulsion  be  farther  aft  than 
its  appropriate  place,  the  vessel  will 
carry  a  weather  helm  by  inclining  to 
the  wind.  It  is  difficult,  however,  to 
determine  how  much  of  the  weather 
helm  is  attributable  to  the  improper 
distribution  of  sail,  inasmuch  as  the 
inequality  in  the  two  lines  of  flotation 
is  the  cause  of  the  weather  helm  to  a 
very  great  extent.  The  altitude  of  the 
centre  of  propulsion  should  be  deter- 


mined with  reference  to  the  vessel's 
performance  when  sailing  before  the 
wind  ;  while  the  area  of  sail  should  be 
resolved  with  reference  to  the  vessel 
when  on  a  wind.  Thus  it  will  be  dis- 
covered that  the  longitudinal  and  the 
vertical  disposition  of  this  point  deter- 
mines all  that  we  require.  Before, 
however,  we  endeavor  to  spread  our 
sails,  it  is  important  that  we  know  the 
ratio  of  stability  the  vessel  may  possess, 
as  the  whole  matter  rests  here  :  if  the 
vessel  have  a  large  amount  of  stability, 
we  may  be  able  to  spread  a  large  area 
of  sail,  but  on  fhe  contrary,  if  we  have 
but  little  stability,  a  small  area  of  sail 
only  will  be  required  ;  hence  it  will  be 
necessary  to  determine  the  amount  of 
stability  we  possess  in  the  manner  we 
have  shown  in  Chapter  3.  It  should 
not  be  forgotten  that  it  is  possible  to 
make  a  vessel  too  stiff  for  a  sailing  ves- 
sel  by  artificial  means  ;  that  is  to  say, 
by  the  distribution  of  cargo  a  vessel 
may  be  made  so  stable,  or  stiff,  that 
her  masts  would  be  endangered  by  tin; 
sudden  efforts  to  right  btnself  when  in- 
clined by  the  wind  or  seav  ^This,  it 
will  be  observed.  Would  not  arise  from 
the  size  or  dimensions  of  the  ship  if 
built  by  the  proportionate  dimensions 
we  have  furnished. 

Before  entering  upon  the  exposition 
of  our  own  views,  we  shall  show  what 
rules    are   adopted    in    some    parts    of 


MARINE  AND  NAVAL  ARCHITECTURE 


401 


Europe.  The  Danish  rule  for  masting 
and  sparring  merchant  ships  is  as  fol- 
lows:  The  centre  of  the  fore  mast  is 
located  at  i  to  i  of  the  length  of  the 
load  or  constructed  line  of  flotation 
from  the  forward  perpendicular;  its 
rake  is  set  down  at  from  i  to  1  de- 
gree— these  being  the  extremes.  The 
centre  of  the  main  mast  from  tt  to  tV 
of  the  load-line,  abaft  the  centre  of  the 
siune;  the  extremes  of  rake  are  set 
down  as  in  that  of  the  fore  mast,  varia- 
ble, being  from  I  to  2  degrees.  The 
centre  of  the  mizen  mast  from  I  to  rs 
of  the  load  water-line  forward  of  the 
after  perpendicular  ;  the  extremes  of 
rake  from  2  to  5  degrees  ;  steve  of  the 
bowsprit  20  to  25  degrees.  For  barks, 
the  centre  of  the  fore  mast  is  placed  i 
to  y  of  the  water-line  aft  of  the  forward 
perpendicular;  the  centre  of  the  main 
mast  I?  aft  of  the  centre  of  the  length 
of  the  load-line  of  flotation  ;  the  mizen 
mast  and  bowsprit  as  in  ships.  In 
brigs,  the  centre  of  the  fore  mast  is  i 
to  t  of  the  length  of  load-line  aft  of  its 
forward  perp^ltcucular,  to  rake  from  1  to 
3  degrtf&s»£. t^e.jmujv'^wast  is  placed 
from  i  to  I  of  the'"" length  of  the  load- 
line  aft  of  its  longitudinal  centre  ;  its 
rake  from  3  to  5  degrees  ;  elevation  of 
the  bowsprit  from  15  to  25  degrees. 
In  -schooners,  the  fore  mast  is  usually 
from  i  to  t  of  the  length  of  the  load-line 
aft  of  the  perpendicular  ;   rake  from  4 


to  10  degrees  ;  the  main  mast  i  to  s  of 
the  length  aft  of  its  longitudinal  centre  ; 
rake  from  6  to  10  degrees;  elevation 
of  the  bowsprit  8  to  10  degrees.  In 
cutters,  sloops  and  yatchs,  the  mast  is 
from  i  to  §  of  the  length  of  the  load- 
line  aft  of  the  forward  perpendicular  ; 
they  sometimes  have  no  rake,  and  the 
greatest  extreme  of  rake  is  set  down  at 
4  degrees  ;  the  elevation  of  the  bow- 
sprit is  set  down  at  from  6  to  8  degrees. 
It  will  be  observed  that  this  descrip- 
tion of  vessels  are  all  sloop-rigged,  and 
that  the  term  cutter  does  not  denote 
in  other  countries  a  vessel  having  two 
masts. 

We  would  deem  the  time  vainly 
spent  in  delineating  every  description 
of  small  craft,  and  the  crude  manner 
of  sparring  them  ;  there  is,  however,  a 
vessel  called  the  Galeas,  unknown  in 
the  waters  of  the  United  States,  and 
used  in  the  Danish  merchant  service  ; 
the  rig  is  very  similar  to  that  of  the 
hermaphrodite  brig  in  this  country, 
with  this  exception — the  main  royal  is 
not  as  taunt  as  that  of  the  fore ;  we 
would  call  the  after  mast  the  main 
mast,  but  it  is  denominated  the  mizen 
mast  by  their  builders.  The  main  or 
fore  mast  is  from  &  to  f  of  the  length 
of  the  water-line  aft  of  the  forward 
perpendicular ;  rake  from  1  to  2  de- 
grees ;  the  mizen  mast  i  of  the  length 
from    the   after  perpendicular    to  the 


402 


MARINE    AND    NAVAL    ARCHITECTURE 


lore  mast,  set  off  forward  of  the  after 
perpendicular;  rake  from  2  to  3  de- 
grees ;  elevation  of  the  bowsprit  from 
16  to  20  degrees.  The  length  of  the 
spars  is  as  follows  :  for  ships  that  have 
a  good  degree  of  stability,  main  mast 
(whole  length)  the  moulded  breadth  of 
the  ship  x  2,  and  the  depth  from  the 
lower  deck  to  the  keelson  added  ;  mast 
head  J  to  I  of  the  whole  length  ;  di- 
ameter 1  inch  to  every  3*  feet  of  the 
same;  the  whole  length  of  the  top- 
mast equals  the  moulded  breadth  and 
the  depth  as  shown  ;  head  £  of  the 
whole  length  of  the  top  mast  ;  diame- 
ter in  the  cap  1  inch  for  3  feet  of 
whole  length  ;  (on  ships  of  small  sta- 
bility t$  or  4  of  the  depth  is  taken  for 
the  lower  and  top  masts;  the  topgal- 
lant is  \  to  %  of  the  top  masts;  in  di- 
ameter 1  inch  to  3  feet  ;  royal  mast  £  to 
§  of  the  foregoing  ;  pole  i  ;  main  yards 
(whole  length)  the  moulded  breadth 
multiplied  by  2  or  II ;  both  of  the  yard 
arms  TV  of  the  yard  ;  diameter  I  inch 
to  every  4  feet  of  length  ;   topsail  yard 

3  of  the   main  yard  ;   both   arms  i   of 
the  whole  length  ;   diameter  1  inch  to 

4  feet  ;  topgallant  yard  §  of  the  topsail 
yard ;  diameter  1  inch  to  4  feet  ;  royal 
between  i  and  %  of  the  foregoing  ;  di- 
ameter 1  inch  to  5  feet  of  length  ;  fore 
mast  is  I  of  the  length  of  the  main  top 
mast  shorter  than  the  main  mast  ;  the 
other  dimensions  are  IS  or  T9o  of  that  of 


the  main  mast ;  mizen  mast  and  its  ap- 
pended spars  are,  for  ships  from  §  to  2 
of  the  main  mast.  In  barks  the  mizen 
mast  is  the  same  length  as  the  main 
mast ;  the  mast  head  is  I  of  this  length, 
and  the  diameter  1  inch  for  every  4  or 
4i  feet  of  length  ;  spanker-boom  I  of 
its  length  over  the  stern  ;  in  diameter 
1  inch  to  every  4  feet  of  length  ;  the 
gaff  is  §  or  3  of  the  boom  ;  diameter  1 
inch  to  SI  feet  of  length  ;  bowsprit  out- 
board I  or  I  of  the  moulded  breadth  ; 
in  diameter  the  size  of  the  fore  mast  ; 
jib-boom  outboard  of  bowsprit  IS  of  the 
foregoing  length.  For  schooners  the 
whole  length  of  the  main  mast  is  3  or 
31  times  the  extreme  breadth,  and  in 
diameter  1  inch  for  4  feet ;  mast  head 
i  to  f  of  the  length  ;  the  fore  mast  from 
I  to  to  of  the  main  mast  ;  the  diameter 
and  length  of  the  head  as  the  main 
mast ;  bowsprit  outboard  i  or  S  of  the 
breadth ;  diameter  same  as  the  fore 
mast  ;  jib-boom  outboard  of  bowsprit 
£  of  the  breadth  ;  diameter  1  inch  per 
5  feet  of  the  whole  length  ;  main  boom 
£  of  the  distance  from  the  main  mast 
to  the  stern  over  the  stern  ;  diameter 
1  inch  for  5  feet;  gaff?  or  3  of  the 
boom  ;  diameter  1  inch  for  4  feet ;  fore 
gaff  4  to  6  feet  shorter  than  main  gaff; 
main  top  mast  2  or  3  feet  longer  than 
half  the  lower  mast ;  fore  top  mast  l 
or  to  of  the  main  ;  lower  yard  13  to  II 
of  the  breadth ;   diameter  I  inch  to  4 


MARINE    AND    NAVAL    ARCHITECTURE. 


403 


feet  :  topsnil  yard  4  of  the  lower  yard  ; 
topgallant  yard  §  of  the  topsnil  yard. 
Tin;  Galeas  have  a  fore  mast  twice 
their  breadth  added  to  twice  their 
depth ;  diameter  I  inch  per  4  feet ; 
mizen  mast  §  of  that  of  the  fore  mast ; 
diameter  1  inch  per  4  feet ;  bowsprit 
outboard  from  H  to  2  times  the 
breadth  ;  diameter  the  mean  of  the 
masts ;  jib-boom  outboard  once  the 
breadth  ;  diameter  1  inch  per  4  feet ; 
fore  top-mast  H  times  the  breadth  ;  di- 
ameter 1  inch  for  every  3i  feet  of 
length  ;  mizen  top-mast  V  of  the  lower 
mast  ;  fore  yard  twice  the  breadth  ; 
topsail  yard  2.  of  the  lower  yard;  di- 
ameter 1  inch  per  4  feet  ;  topgallant 
yard  3  of  the  topsail  yard;  diameter  1 
inch  per  3k  feet ;  fore  boom  2  to  4  feet 
shorter  tl^an  the  distance  between  the 
masts  ;  diameter  1  inch  per  3?  feet  ; 
mizen  boom  1£  to  li  times  the  breadth; 
gaffs  are  §  of  the  booms  ;  fore  mast 
head  i  of  the  length  of  the  mast  above 
deck;  mizen  mast  head  i  of  the  whole 
length  of  the  mast.  Sloops,  if  vessels, 
have  a  large  amount  of  stability,  the 
length  of  the  load-line  of  flotation  is 
the  length  of  the  mast  ;  if  an  ordinary 
amount  of  stability,  3  times  the  breadth; 
diameter  1  inch  per  4  feet ;  head  i  of 
the  length  of  the  mast  ;  top-mast  the 
length  of  the  lower  mast  from  the  deck 
to  the  tressel-trees  ;  bowsprit  outboard 
2  to  3  feet  more  than  the  breadth  ;   jib- 


boom  §  to  3  the  length  of  the  outboard 
part  of  the  bowsprit ;  boom  2  to  6  feet 
over  the  stern  ;  gaff  is  §  to  3  of  the 
boom.  Cutters  and  yachts  are  sparred 
in  the  same  manner.  The  Danish 
theory  requires  the  centre  of  effort  (or 
as  we  have  termed  it,  the  centre  of  pro- 
pulsion) oft  he  sails  of  square-rigged  ves- 
sels to  be  2]o  to  3'o  of  the  length  between 
the  perpendiculars  forward  of  the  cen- 
tre of  the  length,  and  li  to  If  of  the 
extreme  breadth  above  the  water-line. 
On  vessels  without  square  sails,  this 
point  may  be  found  at  or  aft  of  the 
longitudinal  centre. 

The  German  mode  of  sparring  ships 
may  be  comprehended  in  the  following 
manner:  let  L  be  the  length  between 
the  perpendiculars  (or  between  the 
rabbets)  on  the  load-line,  and  B  the 
moulded  breadth  ;  centre  of  the  fore 
mast  =  .16  xL  aft  of  the  forward  per- 
pendicular; rake  iofan  inch  per  foot; 
centre  of  main  mast  .071  *  L  aft  of  the 
centre  of  length  ;  rake  i  inch  per  foot; 
mizen  mast  A  x  L  forward  of  the  after 
perpendicular  ;  rake  1  inch  per  foot  ; 
length  of  the  main  mast  =  2.45  x  B; 
diameter  1  inch  per  3  feet  ;  mast  head 
■£b  of  the  mast  ;  top-mast=f  to  t  of  the 
mast ;  diameter  1  inch  per  3  feet ; 
head  .12  of  its  length  ;  topgallant  mast 
=  5  of  the  length  of  tin*  fore  mast  ;  1 
inch  per  3  feet  of  length  for  diameter; 
royal  mast  *-  of  the  former,  and  to  this 


404 


MARINE    AND    NAVAL    ARCHITECTURE. 


add  the  pole  I  of  the  royal  mast ;  fore 
mast  is  in  all  its  dimensions  H  of  the 
main  mast  ;    fore-top,    topgallant    and 
royal  mast=M  of  that   of  the   main  ; 
the  length  of  the  mizen  mast=T9o,  and 
diameter  I  of  the  main  top-mast ;    the 
other  top-masts  are  £  of  the  main  top- 
mast, and    the    diameter  §   of  them; 
bowsprit  outboard  =.8  x  B  ;   elevation 
4  to  5  inches  per  foot ;    jib-boom   the 
outboard  of  bowsprit  .68  x  B  ;  diame- 
ter .6  of  an  inch  per  foot  of  this  length  ; 
flying  jib-boom  outboard  of  jib-boom 
.51  x  B  ;  diameter  .5   of  an  inch   per 
foot  of  this  length  ;   main  yard  whole 
length  .49  x  L  ;  diameter  1  inch  per  4 
feet;  both  arms  A  of  the  length  ;  top-sail 
yarc]=.376  x  L;  diameter   1  inch  per 
4   feet  of  length  ;  both  arms   .117  of 
the  length  ;  topgallant  yard  .258  x  L ; 
1  inch  per  4  feet  of  diameter  ;  arms  r\ 
of  the  length  ;  royal  yard  .174  x  L ;    1 
inch  for  every  4  feet  of  length  ;    arms 
TV  of  the  length;  fore  yards  are  as  the 
main  yards,  or  i  of  the  same  ;    mizen 
or  cross-jack  yards  are  2  of  the  main 
yard  ;    fore  gaff  .207  x  L  ;    diameter  1 
inch  per  4i  feet ;   main  gaff  .167  x  L ; 
diameter  1  inch  per  4  feet ;   mizen  or 
spanker  gaff  .207  x  L  ;  diameter  1  inch 
for   4    feet  ;    mizen   or   spanker    boom 
.3  x  L ;   1    inch    per   34   to    4    feet  of 
length  ;  fore  leech  of  stay-sail  .6  of  its 
stay  ;  foot  leech  .75  x  B  ;   fore   leech 
of    jib    .75    of    its    stay ;     foot    leech 


.1  x  B  ;  flying-jib   fore  leech  .5  of  its 

stay  ;   foot  leech  .7  x  B. 

In  locating  the  masts  in  brigs,  the 
centre  of  the  fore  mast  =  £  of  the  length 
of  the  load-line  forward  of  its  middle  ; 
rake  I  of  an  inch  per  foot ;  centre  of 
the  main  mast  i  of  the  water-line  aft  of 
its  middle  ;  rake  3  of  an  inch  per  foot ; 
all  the  other  dimensions  as  in  ships. 

In  France  the  following  is  the  ride 
by  which  ships  and  barks  are  sparred : 
Let  L  be  the  length  between  the  rab- 
bets on  deck  ;  B  the  moulded  breadth  ; 
centre  of  fore  mast=.29  x  L  forward 
of  the  middle  of  the  water-line  ;  rake 
TV  of  the  foot  to  each  of  length  ;  centre 
of  main  mast  .155  x  L  aft  of  the  lon- 
gitudinal centre  of  the  length  of  water- 
line  ;  rake  h  of  the  foot  ;  mizen  mast 
.365  x  L  aft  of  the  longitudinal  centre 
of  length  ;  rake  I  of  the  foot  ;  whole 
length  of  the  main  mast  2.33  x  B  ;  di- 
ameter 1  inch  per  3?  feet  ;  mast  head 
t  of  the  length  ;  fore  mast  whole  length 
2.25  x  B  ;  diameter  1  inch  per  3t  feet ; 
mast  head  1  of  the  length  ;  mizen  mast 
whole  length  2.22  x  B  ;  diameter  1 
inch  per  4  feet  ;  mast  head  t  of  the 
length  ;  bowsprit  outboard  .75  x  B  ;  di- 
ameter as  that  of  the  fore  mast  ;  jib- 
boom  of  the  outboard  part  of  bowsprit 
.66  x  B  ;  diameter  i  of  the  bowsprit  ; 
flying  jib-boom  of  the  outboard  part  of 
jib-boom  .5  x  B  ;  diameter  s  of  thVjib- 
booin  ;   main    yffrd=5  x  L;   diameter 


MARINE    AND    NAVAL    ARCHITECTURE. 


405 


1  inch  per  4  feet  ;  both  arms=}  of 
I  he  whole  length  ;  the  fore  yard  same 
as  main  ;  topsail  yards  .375  x  L  ;  di- 
ameter 1  inch  per  4  feet  ;  both  arms 
I  of  the  length  ;  topgallant  yards 
25  x  L;  diameter  1  inch  per  4  feet ; 
both  arms  i  of  the  length  ;  royal  yards 
.184  x  L  ;  diameter  1  inch  to  3i  feet 
of  length  ;  botli  arms  i  of  the  length  ; 
top  masts  1.25  x  B  ;  diameter  1  inch 
per  3  feet;  head  4  ;  topgallant  mast 
.66  x  B  ;  diameter  1  inch  per  3  feet  ; 
royal  masts  .66  x  B  ;  diameter  1  inch 
per  5  feet  ;  pole  i  ;  mizen  top  masts 
1.7  x  B  ;  1  inch  diameter  for  5  feet  ; 
pole  i;    fore   trysail,  or   fore    spencer 

2  x  L  ;  diameter  1  inch  to  4  feet  ; 
nain  spencer  gaff  .125  x  L  ;  diameter 
1  inch  to  4  feet  ;  spanker  boom,  or 
mizen  boom  .25  x  L  ;  diameter  1  inch 
per  4  feet;  gaff  .154  x  L  ;  diameter  1 
inch  per  Si  feet.  The  distribution  for 
brigs  are  as  follows :  location  and  di- 
mensions  the  same  as  those  of  barks, 
except  the  boom  sail,  or  spanker,  which 
equals  .483  x  L  ;  diameter  1  inch  per 
5  feet  ;  gaff  .34  x  L  ;'  diameter  1  inch 
per  4i  feet ;  the  jibs  are  t lie  same  as  on 
barks  ;  flying  jib  fore  leech  .5  of  the 
stay  ;  the  foot  leech  .7  x  B  jib  fore 
leech  .75  of  its  stay  ;  foot  leech  1  x  B  ; 
stay-sail  fore  leech  .6  of  the  stay;  foot 
leech  .75  x  B.  The  schooner  brig,  or 
as  \V  is  termed  in  the  United  States, 
hermarAhioditcbrig,  htive  the  centre  of 


the  fore  mast  .25  x  L  forward  of  the 
middle  of  the  water-line ;  rake  .0S3 
feet  per  foot ;  centre  of  main  mast 
.125  x  L  aft  of  the  middle  of  the  water- 
line  ;  rake  .25  per  foot  ;  (L  and  B 
represent  the  same  as  on  ships  and 
barks  ;)  main  mast  whole  length  2.895 
x  B  ;  diameter  tV  of  the  length  ;  head 
tV  ;  fore  mast  whole  length  2.25  x  B  ; 
diameter  TV  of  the  length  ;  head  i  ;  bow- 
sprit outboard  .75  x  B  ;  diameter  as 
the  fore  mast  ;  jib-boom  of  the  out- 
board of  bowsprit  1.15  x  B  ;  diameter  i 
of  the  bowsprit  ;  flying  jib-boom  the 
outboard  of  jib-boom  .5  x  B;  diameter 
f  of  the  jib-boom  ;  main  top-mast  1.8 
x  B  ;  diameter  4V  ;  pole  I ;  fore  top  mast 
1.25  x  B  ;  diameter  Tv  ;  head  4  ;  fore 
topgallant  mast  .666  x  B ;  diameter  1 
inch  per  3  feet  ;  fore  royal  mast  .68  x 
B  ;  diameter  1  inch  per  4  feet  ;  pole 
J3  ;  fore  yard  .53  x  L  ;  diameter  is  ;  both 
arms  A  ;  fore  top-sail  yard  .39  x  L ; 
diameter  &  ;  both  arms  \  ;  fore  topgal- 
lant yard  .25  x  L  ;  diameter  .02  ;  both 
arms  4  ;  fore  royal  yard  .184  x  L  ;  di- 
ameter .02  ;  both  arms  4  ;  fore  gaff 
25  x  L  ;  diameter  1  inch  per  3*  feet  ; 
main  gaff  .3  x  L  ;  diameter  1  inch  per 
Si  feet  ;  main  boom  .535  x  L  ;  diame- 
ter 1  inch  per  4  feet ;  steve  of  the  bow- 
sprit from  a  horizontal  line  .42  feet. 

The  English  mode  of  sparring  ships 
is  as  follows:  Let  L  be  the  length  be- 
tween the  stem  and  post  on  deck,  and 


406 


MARINE   AND    NAVAL    ARCHITECTURE. 


B  1  he  breadth  to  the  outside  of  the 
wales ;  whole  length  of  main  mast 
~;  diameter  i  per  3  feet  ;  fore  mast 
I. of  the  main  mast;  mizen  mast  3  of 
the  main ;  diameter  §  of  the  main 
mast  ;  main  top-mast  f  of  the  main 
mast  ;  diameter  1  inch  per  3  feet  ;  fore 
top-mast  I  ofthe  main  top-mast;  mizen 
top-mast  f  ;  diameter  tV  of  the  main 
top-mast  ;  topgallant  mast  i  of  the 
top-mast  ;  diameter  1  inch  per  3  feet ; 
royal  masts  £  ofthe  topgallant  masts  ; 
diameter  §  of  the  topgallant  masts; 
whole  length  of  bowsprit  f  of  the  main 
mast,  outboard!  of  this  length  ;  diame- 
ter as  that  ofthe  fore  mast;  jib-boom 
outside  of  cap  of  same,  as  the  bowsprit 
outboard  ;  diameter  1  inch  for  2i  feet 
of  length  ;  flying  jib-boom  f  ofthe  jib- 
boom  ;  diameter  1  per  3  feet ;  main 
yard  I  of  the  main  mast  ;  diameter  .7 
per  3  feet  ;  fore  yard  1  ofthe  main  yard  ; 
mizen,  or  cross-jack  yard,  same  as  the 
fore  top-sail  yard  ;  diameter  I  per  3 
feet ;  main  top-sail  yard  4  of  the  main 
yard  ;  diameter  S  per  3  feet  ;  fore  top- 
sail yard  £  of  the  main  top-sail  yard  ; 
mizen  top-sail  yard  I  of  the  main  top- 
sail yard  ;  topgallant  yard  f  ofthe  top- 
sail yards  ;  royal  yards  i  ofthe  top-sail 
yards  ;  mizen  boom  as  the  main  top- 
sail yard  ;  gaff  I  ofthe  boom  ;  diame- 
ter §  for  3  feet  of  length. 

The    rule  for    masting  ships  in  the 
United    States   is    doubtless   the    most 


variable  on  the  globe  ;  the  most  promi- 
nent builders  each  profess  to  have  a 
mode  peculiar  to  himself.  We  have 
taken  from  several  of  the  best  propor- 
tioned double-decked  freighting  ships 
some  tangible  results  ;  not,  however, 
as  to  the  mode  of  adapting  the  stations 
and  dimensions  to  the  peculiarities  of 
the  model,  for  this  would  be  admitting 
that  ships  are  thus  sparred,  which  we 
do  not.  We  cannot  entertain  the  most 
distant  idea  that  any  system  is  adopted 
in  this  more  than  in  any  other  country 
of  sparring  ships  or  other  vessels — all 
the  changes  that  are  made  from  the 
common  rules,  or  well-known  usages, 
are  made  in  accordance  with  the 
opinion  of  the  builder,  without  refer- 
ence to  the  lateral  resistance,  the  very 
basis  of  propulsion  by  sails;  but  while 
American  ship-builders  vary  from  the 
rules  of  a  stereotyped  age,  there  is  good 
reason  for  the  belief  they  will  yet  re- 
cognize a  system  worthy  of  themselves, 
ofthe  age,  and  ofthe  country  in  which 
they  live.  The  following  is  the  result 
of  the  deductions  referred  to  : — Take 
of  760  parts  of  load-line  from  aft  side 
of  stem  to  fore  side  of  post  ;  150  parts 
to  centre  of  fore  mast  ;  from  thence 
to  centre  of  main  mast  264  parts  ;  from 
thence  to  centre  of  mizen  mast  211 
parts,  and  135  parts  will  remain  ;  U  of 
the  length  on  load-line  should  be*  the 
length  of  the  main  mast ;    fore*  *nast  -I? 


MARINE    AND    NAVAL    ARCHITECTURE 


407 


of  the  main  mast  ;  mizen  mast  fj  of 
the  main  mast  ;  main  top-mast  f°  of 
the  main  mast  ;  main  topgallant  mast 
il  of  the  main  top-mast  ;  royal  U  of 
the  topgallant  ;  sky-sail  mast  *J  of  the 
royal ;  main  yard  1  of  the  length  of  the 
main  mast  ;  main  top-sail  yard  if  of 
the  lower  yard  ;  main  topgallant  yard 
11  of  the  top-sail  yard  ;  main  royal  If 
of  the  topgallant  ;  main  sky-sail  If  of 
the  royal.  The  fore  top-mast,  topgal- 
lant and  royal  should  bear  the  same 
ratio  to  the  lower  masts  that  the  main 
does  ;  likewise  the  mizen  top- mast, 
&c.  The  fore  yard,  top-sail  yard,  top- 
gallant and  royal  will  stand  in  the  same 
ratio  as  the  main  ;  the  mizen  likewise 
will  stand  so  related;  as  a  consequence 
the  fore  yard  will  be  H  of  the  main 
yard  ;  and  the  fore  top-sail  yard  if  of 
the  lower  yard  ;  the  topgallant  fj  of 
the  top-sail  yard,  &c.  ;  the  cross-jack 
yard  \i  of  the  main  yard  ;  mizen  top- 
sail yard  if  of  the  cross-jack  yard  ;  bow- 
sprit outboard  £  of  the  fore  mast  ;  jib- 
boom  \\  of  the  outboard  part  of  bow- 
sprit ;  spanker-boom  *  the  length  of 
the  fore  mast  ;  gaff!!  of  the  length  of 
the  boom.  This  rule  will  also  apply 
to  brigs. 

The  following  method  is  sometimes 
adopted  for  proportioning  the  spars 
of  a  ship — main  mast  2i  times  the  ship's 
beam  ;  fore  mast  equal  to  I  of  the  main 
mast  ;  *nizen    mast   equal   to  t  of  the 


main  mast  ;  bowsprit  §  of  main  mast  ; 
j  inboard  ;  main  top-mast  I  of  the  main 
mast ;  main  topgallant  mast  1  of  the 
main  top-mast,  exclusive  of  the  pole, 
which  is  usually  i  of  the  topgallant 
mast  ;  fore  top-mast  !  of  the  fore  mast  ; 
fore  topgallant  mast  i  of  the  length  of 
the  fore  top-mast  exclusive  of  pole, 
which  is  as  on  the  main  ;  mizen  top- 
mast f  of  the  mizen  mast;  mizen  top- 
gallant mast  i  of  the  length  of  the 
mizen  top-mast ;  pole  as  fore  and  main; 
jib-boom  length  of  the  bowsprit,  if  of 
which  is  outside  of  cap  ;  main  yard 
twice  the  ship's  extreme  breadth  ; 
main  top-sail  yard  §  of  the  main  yard  : 
main  topgallant  yard  S  of  the  main  top- 
sail yard  ;  fore  yard  »  of  the  main  yard  ; 
fore  top-sail  yard  §  of  the  fore  yard  ; 
fore  topgallant  yard  I  of  the  fore  top- 
sail yard  ;  royal  yards  s  of  the  length 
of  the  respective  topgallant  yards  ; 
cross-jack  yard  same  as  main  top-sail 
yard ;  mizen  top-sail  yards  same  as 
main  topgallant  yards ;  mizen  topgal- 
lant yards  two-thirds  of  the  mizen  top- 
sail yard.  Sprit-sail  yards  are  some- 
times carried,  and  are  £  of  the  fore  top- 
sail yard  ;  spanker-boom  the  length  of 
the  fore  top-sail  yard  ;  mizen  gaff  is  of 
the  spanker  boom.  Top-sail  yard  arms 
are  usually  longer  than  others,  in  con- 
sequence of  their  being  oftener  reefed, 
and  the  arms  should  be  adapted  to  the 
hauling   out  of  the  close  reef  earing. 


40S 


MARINE    AMD    NAVAL    ARCHITECTURE, 


Masts  are  placed  often  by  the  following 
rule :  divide  the  length  of  the  upper 
deck  between  stem  and  post  into  360 
equal  parts;  place  the  fore  mast  on 
the  69th  from  forward  ;  the  main  mast 
124  parts  from  the  fore  mast  ;  the 
mizen  mast  on  the  99th  part  from  the 
main  mast  ;  rake  of  fore  mast  3  of  an 
inch  to  every  foot  of  length  ;  main 
mast  I ;  mizen  mast  1  inch ;  steve  of 
bowsprit  4*  inch  to  each  foot  of  length 
from  a  horizontal  line. 

The  methods  for  masting  schooners 
is  so  variable  that  little  tangible  infor- 
mation can  be  derived ;  the  hoist  of 
sails  ranging  from  twice  to  2§  times 
the  breadth  of  beam.  The  masts  are 
sometimes  stationed  in  the  following 
order :  divide  the  length  of  the  deck 
into  756  parts  ;  take  192  from  forward 
for  the  centre  of  the  fore  mast ;  258 
from  the  centre  of  the  fore  mast  to 
that  of  the  main;  and  336  parts  for 
the  foot  leech  of  the  fore  sail,  and  408 
for  the  foot  leech  of  the  main  sail ;  one 
half  of  the  latter  for  the  head  leech  of 
both  sails;  348  parts  for  the  foot  leech 
of  the  jib.  These  proportions  apply 
principally  to  fast  sailing  coasting  ves- 
sels, but  flat  wide  schooners  with 
centre-boards  have  a  greater  propor- 
tion of  sail ;  there  is  no  rule  that  is  in- 
variable. The  schooners  of  the  United 
States  are  not  built  like  our  ships,  prin- 
cipally  in   the  large  cities  ;    they   are 


built  wherever  timber  and  capital  a»re 
found,  and  water  enough  to  launch 
them  ;  hence  the  reason  why  such  di- 
versity in  dimensions,  shape  and  distri- 
bution of  sail.  For  sloops  the  spars 
are  less  variable  :  hoist  of  main  sail  2i 
times  the  breadth  ;  foot  leech  3  times 
the  breadth  added  to  the  depth  ;  after 
leech  3  breadths  added  to  3  depths  of 
hold  ;  jib-stay  same  as  foot  leech  of 
main  sail  ;  after  leech  of  jib  same  as 
hoist  of  main  sail;  head  of  main  sail  1 
breadth  and  3  depths  added  ;  foot  leech 
of  jib  the  same;  station  of  mast,  'i  of 
the  breadth  from  the  forward  part  of 
deck  ;  rake  I  inch  to  the  foot ;  schoon- 
ers from  I  to  I  inch.  With  regard  to 
the  rake  of  masts,  there  seems  to  be 
an  error  that  prevails  almost  univer- 
sally ;  the  original  design  in  raking 
masts  is  to  get  lifting  power  in  vessels 
with  fore  and  aft  sails  ;  both  masts  are 
raked  as  if  both  ends  could  be  lifted 
with  the  power  of  the  wind  at  the  same 
time.  It  must  be  plain,  we  think,  that 
if  the  vessel  displaces  a  volume  of  water 
equal  in  weight  to  the  weight  of  the 
vessel,  that  of  the  How  is  depressed  by 
the  power  of  the  wind ;  the  centre  of 
propulsion  is  too  high  or  too  far  \'oqm> 
ward  ;  hence  it  follows,  that  whatever 
power  is  expended  in  endeavoring  to 
lift  the  vessel,  is  lost  in  propelling  her 
onward;  and  if  the  vessel's  head  is  de- 
pressed, it  is  yjot  because  the  masts  do 


MARINE    AND    NAVAL    ARCHITECTURE. 


409 


not  rake  enough,  but  because  the  alti- 
tude   of  the    centre    of  propulsion   is 
above  a  just  proportion  of  this  lifting 
tendency,  consequent  upon  the  rake  ; 
were  this  what  it  is  assumed  to  be,  the 
proper  mode  would  be  to  rake  the  fore 
mast  only  ;   it,  however,  should  be  re- 
membered, that  any  very  considerable 
rake  to  a  vessel's  mast  has  a  tendency 
to  depress  the  vessel  when  an  inclina- 
tion   takes    place  ;    the   lifting    power 
operates  against  us  when  the  vessel  is 
careened  to  any  very  considerable  ex- 
tent.     To  mariners  it  has  been  a  mat- 
ter  of  wonder  how  the   vessel's    bow 
could  be  so  much  depressed  while  the 
head  sails  were  set  at  a  powerful  lifting 
angle  ;    the  bellying-   of  the    sail  itself, 
were  there  no  other  influence,  is  de- 
pressive in  its  tendency  ;   and  although 
by  raking  the  masts  of  vessels  we  move 
the  centre  of  propulsion  farther    aft, 
which  is  in  itself  important  when  re- 
quired, yet  the  gain  in  lifting  the  ves- 
sel is  much  less  than  is  generally  sup- 
posed ;  were  the  masts  to  be  set  direct- 
ly perpendicular  to  base-line,they  would 
appear  to  incline  fbrward,  and  indeed 
they  actually  would    so   incline    when 
f0ke  vessel  was  under  a  press  of  canvass. 
We   are  not  opposed   to  the  raking  of 
vessels'  masts  ;   enough  to  impart  life  is 
sufficient,  and  this  amount  would  not 
materially  influence  the  vessel.      It  has 
been  found  necessary  to  rake  the  mizen 


mast  of  ships  more  than  the  fore  mast, 
in   consequence  of  the  mizen   top-sail 
being   in  close  proximity  to  the  main, 
causing  the  current  of  wind  when  leav- 
ing   the    main    top-sail    to    strike    the 
weather  leech  of  the   mizen    top-sail 
aback,  when  close  haul  upon  a  wind  ; 
but  while  it  is  necessary  in  many  cases 
to  rake  the  mizen  mast  more,  it  is  not 
necessary  to  extend  the  special  grant 
to   the   main,  inasmuch  as  the   extra 
rake  to  the  mizen  was  designed  to  clear 
the  two  top-sails;   and  it  must  be  quite 
apparent,  that  to  rake  the  main  mast 
more  than  the  fore  mast,  (because  the 
mizen  mast  has  been,)  is  to  counteract 
the  effects  of  what  has  been  gained  by 
the    extra    rake    of  the    mizen.      We 
readily   admit   that   to  the    eye    there 
seems  to  be  a  fair  distribution  of  rake, 
because  we  have  been  accustomed  to 
see  the  masts  of  a  ship  thus  disposed  ; 
but  the  principles  of  utility  owes  no 
allegiance   to   this    false   standard  :    it 
must  be  quite  clear,  that  if  the  main 
mast  were  raked  less,  the  mizen  would 
require  less  ;   schooners  and  sloops  fur- 
nish a  clear  exemplification  of  the  po- 
sition :    while   the    schooner's   rake    is 
variable,  ranging  from  3  to    li  inches 
to  the  foot,  the  sloop  ranges  from  i  to 
i  of  an  inch  to  the  foot  ;  the  only  ex- 
ception to  this  rule  worthy  of  notice, 
is  the  small  fishing  smack. 

It  is  notoriously  true  that  the  sloop 


52 


410 


MARINE   AND    NAVAL    ARCHITECTURE. 


can  shape  her  course  closer  to  the  wind 
than  the  schooner.  We,  however,  are 
frank  to  admit,  that  this  discrepancy  in 
the  schooner  is  not  wholly  consequent 
upon  (lie  rake  of  her  masts.  The  wind 
will  act  more  effectively  on  one  sail 
than  two,  though  there  be  even  some- 
what more  area  in  the  two  than  in  the 
one.  This  may  be  accounted  for 
upon  philosophical  principles  :  when 
the  schooner  is  on  a  wind,  the  after 
leech  of  the  jib  bellies  or  bows  to  lee- 
ward less  than  the  part  just  forward  of 
the  leech  ;  this  is  because  the  leech  of 
the  sail  has  the  strain  of  the  jib-sheet 
to  keep  it  taut  ;  the  wind  passing  out 
of  the  jib  strikes  the  fore  sail  on  the 
lee  side;,  and  destroys  its  efficiency  as 
far  as  its  influence  is  felt.  Just  so  with 
the  main  sail  :  the  wind  leaving  the 
fore  sail  operates  in  the  same  manner. 
It  is  true  that  the  sloop  has  the  same 
difficulty  with  her  jib,buther  main  sail  is 
large,  and  the  proportionate  draw-back 
is  small,  being  only  on  one  sail ;  squ  are- 
na-fired vessels  have  an  advantage  that 
fore  and  aft  ones  do  not  possess  ;  not  be- 
cause their  sails  are  larger,  which  is 
not  the  case,  but  because  they  are  ena- 
bled to  trim  the  sails  much  nearer  the 
perfect  plane,  consequently  this  dele- 
terious influence  of  one  sail  upon 
another  is  not  felt  so  much. 

It  will  appear  obvious  to  the  discern- 
ing mind  that  the  square  top-sail  can 


be  prevented  from  bellying  out  to  lee- 
ward much  better  than  the  main  sail 
of  the  schooner  or  sloop,  for  the  mani- 
fest reason  that  the  square  sails  of  the 
ship  can  be  sheeted  home  at  both  cor- 
ners, and  if  the  yards  should  bend  un- 
der the  strain  in  sheeting  home,  the 
lifts  can  be  kept  sufficiently  taut  to 
counteract  the  extra  strain  ;  hence  we 
discover  that  the  flow  of  fore  and  ail 
sails  is  much  greater  than  that  of  i  u 
square  sails,  in  consequence  of  the  ina- 
bility to  spread  the  fore  and  aft  sails  as 
near  the  perfect  plane. 

With  regard  to  the  location  of  the 
masts  of  ships,  brigs,  schooners  or 
sloops,  the  grand  secret  does  not  lie  in 
the  mere  location  of  the  masts,  but  in 
the  locality  of  the  centre  of  propulsion. 
This  point,  like  the  centre  of  gravity, 
represents  all  the  forces  that  propel 
the  ship.  For  example  :  the  three 
top-sails  of  a  ship  are  supported  by  the 
yards  ;  the  yards  are  supported  by  the 
masts,  and  the  masts  are  supported  and 
stayed  by  the  hull  ;  but  is  it  not  plain 
that  either  or  all  the  top-saile  may  be 
held  in  equilibrio  by  a  single  four- 
stranded  rope  of  a  size  adapted  to  the 
force?  To  accomplish  this,  it  is  only 
necessary  to  find  the  centre  of  gravity 
of  the  sail;  that  is  to  say,  find  that 
point  around'which  there  is  an  equal 
area  of  canvass,  whether  vertical  or 
horizontal,  as  we  have  shown  in  Plate 


MARINE  AND  NAVAL  ARCHITECTURE. 


411 


1  and  Plate  20;  this  point  being  found, 
we  may  assume  the  Four-stranded  rope 
to  be  unlayed  a  suitable  distance  from 
one  end ;  the  standing  part  being 
stretched  and  kept  in  horizontal  line 
with  (he  centre  of  gravity,  and  made 
fast  ;  let  the  four  strands  be  made  fast 
to  the  four  corners  of  the  sail,  is  it  not 
plain  that  the  effect  is  the  same  ;is 
though  the  wind  filled  the  sail  when 
suspended  to  the  yard  ?  and  will  not 
the  rope  sustain  nil  the  force  conse- 
quent upon  the  filling  of  the  sail  by 
the  wind,  even  though  the  sail  were 
loosed  from  the  yard  ?  and  if  it  is  the 
ease  in  one  sail,  is  it  not  so  with  regard 
to  ail  the  sails  ?  and  may  the}  not  all 
be  represented  in  the  same  manner? 
It  is  quite  a  common  expression  (in 
reference  to  the  propelling  power  of  a 
ship)  to  say  that  her  fore  mast  (for 
example)  is  too  far  forward,  or  that 
she  has  too  much  head  sail,  or  that  she 
has  not  enough  head  sail  ;  that  her 
masts  are  too  far  aft  :  these,  we  say, 
are  common  expressions,  and  familiar 
to  almost  every  commercial  man  ;  but 
is  not  the  same  effect  produced  when 
the  sails  on  the  fore  mast  are  reduced 
or  increased  ?  We  expect  by  moving 
(lor  example)  tin;  fore  mast  farther  aft, 
with  all  the  sails  unaltered,  to  reduce 
the  pressure  ou^  the  how;  not  by  re- 
ducing the  sails,  hut  by  bringing  the 
propulsory    power    of    the    fore    mast 


nearer  the  middle  of  the  ship  ;  if  tin; 
mast  remains,  tin;  same  thing  may  he 
effected  by  reducing  the  sails;  these 
remarks  apply  to  the  other  masts. 
The  difficulty  lies  here-  :  we  have  be- 
come accustomed  to  see  the  fore  mast 
nearly  as  high  as  the  main  mast,  and 
the  mizen  mast  still  shorter  than  the 
fore  mast,  and  a  certain  adaptation  of 
the  yards  ;  and  while  there  is  no  mani- 
fest departure  from  this  hoary  practice, 
all  is  well;  but  let  the  masts  remain, 
and  reduce  or  increase  (he  sail  by 
adapting  it  to  the  model,  and  doubtless 
the  objection  will  at  once  he  heard. 
On  the  ordinary  model  the  difference 
would  not  in  many  instances  he  mani- 
fest, but  let  the  ship  be  designed  for 
speed,  and  the  centre  of  buoyancy  lo- 
cated at  or  aft  of  the  longitudinal  cen- 
tie  of  length,  (inasmuch  as  this  locality 
has  been  proved  to  be  the  best  for  high 
speed,)  and  the  discrepancy  w  ill  be  but 
too  manifest.  When  the  length  is  di- 
vided into  a  given  number  of  parts, 
without  reference  to  the  breadth,  for 
stationing  the  masts  of  a  ship,  it  must 
be  plain  that  the  rule  would  place  the 
masts  in  a  scow  of  the  same  length  in 
precisely  the  same  location  as  those  of 
the  ship;  and  it  does  not  follow  that 
because  the  ship  is  of  uncommon  length 
that  she  is  able  to  bear  sail  in  propor- 
tion ;  neither  will  it  answer  to  have 
exclusive   reference  1o  the  breadth  '  in 


412 


MARINE    AND    NAVAL    ARCHITECTURE 


masting  and  sparring  ships  ;  nor  yet 
to  the  centre  of  buoyancy,  to  the  ex- 
clusion of  all  other  points.  There  is 
another  point  in  connection  with  the 
centre  of  buoyancy  that  should  be  no- 
ticed, if  we  would  have  the  ship  work 
well.  We  will  draw  our  deductions 
from  well-proportioned  ships  ;  that  is  to 
say,  those  on  which  the  greatest  trans- 
verse section  is  at,  or  very  near  the 
centre  of  the  vessel  ;  and,  as  a  conse- 
quence, in  the  present  state  of  advance- 
ment, the  centre  of  buoyancy  would 
be  about  the  centre  or  somewhat  for- 
ward of  that  locality.  We  will  now 
determine  the  longitudinal  centre  of 
the  lateral  resistance  ;  this  point  can- 
not readily  be  determined  from  the 
draft  ;  hence,  in  order  to  make  the 
subject  clear,  we  shall  resort  to  other 
means,  and  adopt  another  medium 
through  which  to  furnish  our  exposi- 
tions. The  model,  we  think,  will  fur- 
nish all  that  we  require  ;  assuming 
that  the  model  of  a  ship  were  varnish- 
ed, it  would  not  be  materially  injured 
by  being  immersed  as  high  as  the  load- 
line  of  flotation  ;  in  order,  however,  to 
secure  an  equilibrium  in  an  upright  po- 
sition, it  will  be  necessary  to  screw  a 
piece  of  batten  on  the  top  extending 
across  the  middle  line  at  some  length, 
ovi  which  a  weight  may  be  secured, 
that  will  cause  the  model  to  equipoise 
transversely  ;  the  batten  being  placed 


on  a  vertical  line  over  the  centre  of 
buoyancy,  let  the  model  now  be  placed 
in  water  as  deep  as  the  load-line  of  flo- 
tation ;  it  may  then  be  assumed  that 
the  model  rests  on  a  sheet  of  still  water, 
of  sufficient  extent  to  be  moved  freely 
in  any  direction,  supported  by  the  cen- 
tre of  buoyancy,  and  that  point  at  the 
centre  of  length  longitudinally.  We 
may  now  determine  the  centre  of  the 
lateral  resistance  in  the  following  man- 
ner :  insert  a  nail  at  the  centre  of  buoy- 
ancy, to  which  connect  a  string,  and 
then  take  the  angle  the  middle  line  of 
the  model  forms  with  the  side  of  the 
box  basin,  or  side  of  whatever  the 
water  and  model  may  be  placed  in ; 
let  the  model  be  drawn  side-ways  by 
the  string  a  considerable  distance,  and 
aoain  take  the  angle  of  the  middle  line  " 
as  before,  when  we  shall  be  able  to  de- 
termine which  end  of  the  model  has 
the  preponderance  of  lateral  resistance; 
the  end  having  the  least  will  have 
moved  the  greatest  distance ;  we  may, 
after  having  adjusted  the  string,  try 
again  ;  not,  however,  before  insert- 
ing another  nail  and  string  of  equal 
weight  on  the  opposite  end  of  the  cen- 
tre of  buoyancy,  to  counteract  the  lev- 
erage of  the  one  we  propel  by  ;  it  will 
be  perceived  that  in  the  first  instance 
the  nail  and  string  were  at  the  centre 
of  buoyancy,  and  was  not  unduly  in- 
clined to  either  the  bow  or  the  stern  : 


MARINE    AND    NAVAL    ARCHITECTURE. 


413 


but  now  in  the  second  trial  we  have 
the  nail  and  siring  on  one  end,  and, 
consequently,  the  same  or  an  equal 
distance  from  the  centre  of  buoyancy, 
on  the  other  end  we  must  append  an 
equal  weight  ;  we  again  take  the  angle 
as  at  first,  and  then  draw  the  model 
side-ways  as  before  ;  we  may  require 
not  only  this  second,  but  several  subse- 
quent trials,  before  we  shall  have  de- 
termined the  correct  location  of  the 
centre  of  the  lateral  resistance  ;  hav- 
ing found  this  point  in  the  manner  de- 
scribed, which  will  most  likely  be  aft  of 
the  centre  of  buoyancy, inasmuch  ns  the 
cavity  of  the  run  augments  the  lateral 
resistance;  in  a  word,  the  impressive 
sameness  in  most  models  leads  us  to 
draw  this  inference  :  if  the  model  be 
that  of  a  ship,  and  be  quite  full,  or  as 
full  as  freighting  ships  usually  are,  the 
centre  of  propulsion  should  be  quite  as 
far  forward  of  the  centre  of  buoyancy 
as  the  centre  of  lateral  resistance  is 
aft  of  the  same  ;  and  the  reason  why 
this  departure  should  take  place,  may 
be  found  in  the  fact  that  the  inequality 
in  shape  of  the  two  lines  of  flotation, 
causes  the  vessel's  bow  to  incline  to 
wind  ;  and  the  reason  will  appear 
mahi&st  if  we  but  remember  that 
from  the  dead-flat  frame  on  the  lee  line 
of  flotation  to  the  wood  ends  the  dis- 
tance is  much  greater  than  on  the 
weather   line,  and    inasmuch    as    the 


pressure  or  resistance  is  met  at  right 
angles  from  the  immersed  surface,  a 
much  greater  amount  of  resistance  is 
found  on  the  leeward  than  on  the  wind- 
ward side  ;  and,  as  a  consequence,  the 
preponderance  of  propulsion  is  required 
on  the  forward  side  of  the  centre  of 
buoyancy,  to  counteract  its  influence. 
On  Plate  20  we  have  shown  the  dis- 
tance of  the  centre  of  propulsion  to 
be  8  feet  forward  of  the  centre  of  buoy- 
ancy, and  yet  the  ship  is  lightly  sparred 
and  has  less  than  the  usual  proportion 
of  head  sail,  while  the  model  exhibits 
less  of  this  leeward  preponderance  than 
perhaps  any  freighting  ship  of  equal 
breadth  and  displacement,  and  yet  her 
performance  warrants  us  in  announc- 
ing the  distribution  to  be  all  that  could 
be  desired  ;  but  this  arrangement  could 
not  be  carried  out  with  equal  success 
on  all  freighting  ships,  and  for  the  fol- 
lowing reason :  the  ship  referred  to 
has  an  equal  distribution  of  buoyancy 
on  each  side  of  the  longitudinal  centre 
at  the  load-line  of  flotation,  which  is 
rarely  the  case  in  sailing  vessels  of  any 
description  ;  but  it  does  not  follow  that 
the  centre  of  the  lateral  resistance  is 
also  in  the  centre  of  length  ;  the  rake 
of  the  stem  causes  a  loss  of  lateral  re- 
sistance on  the  bow,  while  the  surface 
of  the  rudder  increased  its  amount  on 
the  after  end;  hence  we  discover  that 
the  centre  of  buoyancy  was  between 


414 


MARINE    AND    NAVAL    ARCHITECTURE. 


The  two  points,  and  about  equidistant 
from  each.  It  must  not,  however,  be 
supposed  that  because  full  ships  re- 
quire more  sail  forward  than  this  ship, 
on  account  of  the  greater  inequality 
in  thr  form  of  the  lines  of  flotation, 
that  the  distance  between  the  centre 
of  buoyancy  and  the  centre  of  propul- 
sion should  be  augmented;  fortius  rea- 
son the  ccut re  of  buoyancy  is  farther 
forward  on  the  full  bow,  and  the  cen- 
tre; of  lateral  resistance  farther  aft  ; 
hence  we  find  that  the  locality  of  those 
points  furnish  an  index  to  the  appor- 
tionate  distribution  of  sail. 

We  have  another  demonstration  in 
Plate  1  ;  there  we  svte  the  centre  of 
propulsion  about  34  feet  forward  of 
the  centre  of  buoyancy,  and  when  we 
remember  that  the  vessel  shown  in 
Plate  L  is  but  about  70  feet  keel,  and 
that  the  other  on  Plate  20  is  about 
170  feet  keel,  we  shall  at  once  recog- 
nize the  analogy  in  the  proportions  o'f 
the  distance  between  the  two  centres 
of  the  two  vessels;  here  we  have 
another  exemplification  of  the  advan- 
tages of  blending  practice  with  science. 
The  vessel  shown  in  Plate  1  furnishes 
an  exhibition  of  the  advancement  of 
science  in  the  Old  word,  while  Plate 
20  fllustn  !S  the  approximation  to 
maturity  in  the  New. 

In   Plate   24  we  are   shown  a  pilot- 
boat  on  which  the  centre  of  buoyancy 


is  aft  of  the  longitudinal  centre:  and 
although  the  form  of  the  vessel  is  such 
as  to  bring  the  centre  of  the  lateral 
resistance  equally  as  far,  if  not  still 
farther  aft,  yet  we  say  this  ride  is 
equally  applicable  to  this  description 
of  vessel,  and  in  some  instances  where 
the  equalization  of  the  form  of  the  two 
lines  of  flotation  is  complete,  the  cen- 
tre of  propulsion  may  be  located  at 
the  centre  of  the  lateral  resistance. 

In  Plate  25  we  have  another  illus- 
tration in  the  sloop  Victorine  ;  this 
vessel,  a  remarkable  fast  sailer  as  we 
have  already  shown,  has  her  centre  of 
buoyancy  somewhat  less  than  2"  f<el 
forward  of  the  longitudinal  centre,  and 
the  centre  of  Literal  resistance  is  About 
3  feet  aft  of  the  longitudinal  eentre,  as 
shown  by  the  sirmark  B  ;  but  this  is 
not  all  :  the  centre  of  propulsion  is 
forward  at  the  same  point  ;  in  this  case 
we  discover  the  centre  of  buoyancy, 
which  is  at  the  sirmark  A,  to  be  near- 
ly 5  feet  forward  of  the  centre  of  late- 
ral resistance.  The  casual  observer 
may  be  able  here  to  discover  the  cause, 
viz.,  the  rake  of  the  stem  forward,  and 
the  preponderance  of  surface  to*  the 
centre-board  on  the  after  side  of  the 
centre  of  length,  in  addition  to  the 
skeig-like  shape  of  the  after  end  of  the 
immersed  part;  in  this  case  the  rake 
relieved  the  bow  to  a  very^onsi  len- 
ble   extent   of  the   effects  of  the    i 


«•«?► 


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UNIVERSITY  OF  CALIFORNIA 

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